PHP the completed note

Web hardware and software Basics

Markup languages like HTML, XML are used for the designing of web pages. For the

presentation and appearance CSS is used.

Common Gateway Interface

CGI is the standard protocol that defines how the web server software can assign the generation

of web pages to a console application. Such applications are known as CGI scripts. They are

written in scripting languages. These scripts are executed by operating system and results are

given back to the web server. But now a day these scripts (PHP, ASP) run directly by the web

server itself or by the extension modules such as mod_pearl, mod_php etc. This is called direct

execution.

Both of these CGI and direct execution can be used to build complex multi page sites. But

direct execution results lower overhead due to the lack of calls to the external interpreter.

Ques: How a PHP script can execute using command line?

Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name

as the command line argument. For example, "php myScript.php", assuming "php" is the

command to invoke the CLI program. Be aware that if your PHP script was written for the Web

CGI interface, it may not execute properly in command line environment.

Server side scripting and Client side Scripting

Server Scripting

It is the web server technology in which user's request is fulfilled by running a script and the

web server generate dynamic pages. It is used to provide the interactive website that interface to

the databases or data stores.

The primary advantage of server scripting is the ability to customize the response based on the

needs, access rights, or queries into databases. In this programmers can write their own server,

client and communication protocol that can be only be used with one another. In earlier days

server scripting was done by the combination of C, Perl and shell scripts using CGI. Eg: ASP/

ASP.Net, PHP, JAVA, Java Script, PERL, Ruby, Lasso, JSP, SMX, Python.

Client Scripting

Client side scripting is the class of computer programs on the web that are executed at the client

side by the user's web browser. These computer programs are written in Dynamic HTML so tat

the web pages to be scripted. ie. Change in content depending on user input, environmental

conditions and variables.

Client side scripts are two types. External Scripts and Embedded scripts.

The scripts can write within the HTML codes then it is called embedded scripts. Sometimes

scripts can write in a separate file and called when needed .This is called external scripts.

When client request, demanded files are sent to the client’s computer by the corresponding web

server. The user's web browser executes the script and displays the document, including visible

output from the script.

Client side may also contain instruction for browser to follow if the user interacts with

document eg: clicking button.

These instructions can be followed without the communication with server. The client side

scripts can see be seen by the users but can't change it.

Server Scripting Client Scripting

1. Done at the server side.

2. Script executed by the web server of server.

3. Produced output can understand by web browser

(DHTML).

4. User can't see source code unless author publishes

code.

5. They have greater access to the information and

functions available on the server.

6. Server side scripts require language interpreter

installed on server regardless of the client's web browser,

OS or System calls.

7. Eg: PHP, ASP

Done at client side

Executed by web browser of client.

Output is the display of execution of script.

User can see source code.

They have great access to the information and

functions available on the user's browser.

Client side scripts do not require any additional

software on the server. But requires web

browser which understands the scripting

language.

Eg; Javascript, VB script.

Web server

Web server is a computer program that is responsible for accepting HTTP requests from clients

and serving them HTTP responses along with optional data contents.

HTML Basics

Hyper Text Markup Language is the first member of SGML (Standard Generalized Markup

Language). It is used to design layout of the documents and to specify Hyperlinks. HTML

contains tags and attributes. Tag is coded HTML command that defines how part of web page

should be displayed. Attribute is a special word used inside the tag to specify additional

information to tag. Eg: bgcolor, size.

Format of HTML:

<HTML>

<HEAD>

<TITLE></TITLE>

<META></META>

<SCRIPT></SCRIPT>

</HEAD>

<BODY> </BODY>

</HTML>

Tags and attributes

WAMP and LAMP

Ques: What are the reasons for selecting LAMP (Linux, Apache, MySQL, Php) instead of

combination of other software programs, servers and operating systems?

All of those are open source resource. Security of linux is very very more than windows.

Apache is a better server that IIS both in functionality and security. Mysql is world most

popular open source database. PHP is faster than ASP or any other scripting language.

Dream weaver

Macromedia Dream weaver 8 is a professional HTML editor for designing, coding, and

developing websites, web pages, and web applications. Whether you enjoy the control of hand-

coding HTML, or prefer to work in a visual editing environment, Dreamweaver provides you

with helpful tools to enhance your web creation experience.

This guide introduces you to using Macromedia Dreamweaver 8 if you’re unfamiliar with any

major aspect of it.The tutorials in this guide lead you through the process of creating a simple but

functional website.

Macromedia Dreamweaver 8 is a professional HTML editor for designing, coding, and

developing websites, web pages, and web applications. Whether you enjoy the control of hand-

coding HTML or prefer to work in a visual editing environment, Dreamweaver provides you

with helpful tools to enhance your web creation experience.

The visual editing features in Dreamweaver let you quickly create pages without writing a line of

code. You can view all your site elements or assets and drag them from an easy-to-use panel

directly into a document. You can streamline your development workflow by creating and

editing images in Macromedia Fireworks or another graphics application, then importing them

directly into Dreamweaver, or by adding Macromedia Flash objects.

Dreamweaver also provides a full-featured coding environment that includes code-editing tools

(such as code coloring and tag completion) and language reference material on Cascading Style

Sheets (CSS), JavaScript, and ColdFusion Markup Language (CFML), among others.

Macromedia Roundtrip HTML technology imports your hand-coded HTML documents without

reformatting the code; you can then reformat code with your preferred formatting style.

Dreamweaver also enables you to build dynamic database-backed web applications using server

technologies such as CFML, ASP.NET, ASP, JSP, and PHP.

Dreamweaver is fully customizable. You can create your own objects and commands, modify

keyboard shortcuts, and even write JavaScript code to extend Dreamweaver capabilities with

new behaviors, Property inspectors, and site reports.

Tomcat

PHP

The PHP Hypertext Preprocessor is a scripting language that allows web developers to create

dynamic content that interacts with databases. PHP is basically used for developing web based

software applications. PHP is faster than ASP or any other scripting language.

PHP History

Macro Tabini is the founder of PHP architecture. Earlier days PHP was Personal Home Page.

PHP developed by Rasmus Lerdorf. Lerdorf created PHP tools to perform tasks such as

displaying his resume and recording how much traffic his page receiving. Then he made a form

interpreter named PHP/FI by combining Common Gateway Interface Binaries (CGI).PHP/FI

can support C language, communicate with databases and can build Simple dynamic web pages.

Lerdorf published PHP in 1995 June 8. Release name was PHP2. It included PERL variables,

form handlings and HTML support.

In 1997 two Israeli developers Zeev Suraski and Andi Gutmans formed PHP3 and its name was

changed to Hypertext Preprocessor. In November 1997 PHP/FT2 is formed and in 1998 PHP3

officially launched.

Zeev and Andi make PHP core named PHP4 by creating Zend Engine I in 1999. Zend Engine is

an open source scripting engine. Zend Engine has licensed by PHP License since 2001. Zend is

combination of Zev and Andi. They also formed Zend Technologies at Rasmat Gan, Israel.

Released PHP4 on 2000 May 22 with Zend Engine II.

PHP5 is created with Zend Engine II and released on July 13, 2004. PHP 5 has the features that

data object extensions.

Late static building

PHP 6 created from PHP 5 by adding some advantages.

register_globals, magic quotes and safe mode are removed. register_globals is a function

that defines whether or not register EGPCS(Environment,GET, POST, Cookie, Server) as

global variables. Magic quotes: is feature that prevents inexperienced developers from

writing code which is vulnerable to SQL injection attack. Safe mode: iS access utility to

troubleshoot.

Supports uni-code, multibyte strings and ASCII characters.

Run in both 32 bit and 64 bit environment

Version number Release Date Features

1 June 8 1995 Personal Home Page

2 November 1 1997 Fastest tool for dynamic page creation.

3 June 6 1998 Zeev and Andi's PHP3

4.0

4.1

4.2

4.3

4.4

4.4.8

May 22 2000

December 2001

April 2002

December 2002

July 11 2005

January 3 2008

Zend Engine.

Super globels ($_GET, $_POST, $_SESSION) added.

register_globels disabled.

Command Line Interpreter added to CGI.

Manpages for phpsize and php_config.

Security enhancement and bug fix.

4.4.9 August 7 2008 More security enhancement.

5

5.1

5.2

5.2.11

5.2.12

5.3

5.3.1

July 13 2004

November 24 2005

November 2 2006

September 16 2009

-

June 30 2009

November 19 2009

Zend Engine II

Compiler variables in PHP Engine

Enable filter extension by default.

Bug and security fix

-

Name space support

Late Static binding

Jump label

Native Closures

Native PHP archives

Garbage collections

Window Support

Persistent connection with MySQL

Ternary shortcuts

php extension

Bug and security fixes.

6 Unicode Support

Alternate PHP cache

Removal of register_globals, magic quotes and safe mode.

PEAR

PEAR is short for "PHP Extension and Application Repository". PEAR is the next revolution in

PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and

distribution system for reusable PHP components. It eases installation by bringing an automated

wizard, and packing the strength and experience of PHP users into a nicely organized OOP

library. PEAR also provides a command-line interface that can be used to automatically install

"packages" . The purpose of PEAR is to provide:

A structured library of open-sourced code for PHP users

A system for code distribution and package maintenance

A standard style for code written in PHP

The PHP Foundation Classes (PFC),

The PHP Extension Community Library (PECL)

A web site, mailing lists and download mirrors to support the PHP/PEAR community

PHP features

Performance: Scripts written in PHP executes faster than other Scripting languages.

Optimized memory manager and third party accelerators improves the performance and

response time.

Portability: PHP is portable to MS Windows, UNIX and Mac OS ,OS/2.

Ease of use: PHP syntax is clear and consistent.

Open Source: PHP has GPL license and so it is freely available without any cost.

Community Support: PHP developing is done through more than 100 of developers

among world.

Third party application Support: PHP supports wide range of databases. It supports

MySQL,postgre SQL ,ORACLE, and Ms SQL Sever.

Automatic Compilation: PHP is interpreted language that is a change made in source

code will test automatically.

PHP3 vs PHP4

PHP4 cannot support oops concepts and Zend engine 1 is used.

PHP5 supports oops concepts and Zend engine 2 is used.

Error supporting is increased in PHP5.

XML and SQLLite will is increased in PHP5.

PHP 5.3 Features

Zend Engine Architecture

Variables and data types

PHP variables contain int, float, double string etc. It is loosely coupled that is the type will

implicitly change the type of variable as needed, depending on the operations being done in

value. PHP variables are identified by $ symbol followed by variable name. Name contains a-z,

A-Z and should start with a letter and then follows _, numbers etc. PHP supports pointers.

Ques: Would you initialize your strings with single quotes or double quotes?

Since the data inside the single-quoted string is not parsed for variable substitution, it’s always a

better idea speed-wise to initialize a string with single quotes, unless you specifically need

variable substitution.

Variables

Variables are temporary storage containers. In PHP, a variable can contain any type of data,

such as, for example, strings, integers, floating-point numbers objects and arrays. PHP is loosely

typed, meaning that it will implicitly change the type of a variable as needed, depending on the

operation being performed on its value. PHP variables are identified by a dollar sign $, followed

by an identifier name. Variables must be named using only letters (a-z, A-Z), numbers and the

underscore character; their names must start with either a letter or an underscore.

Indirect Referencing of Variables

In PHP it is possible to create a variable whose name is contained in another variable.

Example:

<?php

$x="John";

$$x="sam";

echo $x;

echo "<br>";

echo $$x;

echo "<br>";

echo $John;

?>

Output

John

sam

sam

Ques: What is the difference between $message and $$message?

$message is a simple variable with a fixed name whereas $$message is a reference variable

whose name stored in $message. Ie if $message contains "var" $$message is the same as $var.

Example:

$a=”abc”;

$aa=”z”;

print($abc); // op is z

print($aa);// op is z

print($a); //op is abc

Data Types

1. PHP's scalar data types

Scalar data is data that only contains a single value. PHP features 6 scalar data types:

Type Description Example values

integer A whole number 7, -23

float A floating point number 7.68, -23.45

string A sequence of characters "Hello", "abc123@#$"

unicode A sequence of Unicode characters "Hello", "abc123@#$"

binaryA sequence of binary (non-Unicode)

characters"Hello", "abc123@#$"

boolean Either true or false true, false

2. PHP's compound data types

Compound data can contain multiple values. PHP has 2 compound data types:

Array: Can hold multiple values indexed by numbers or strings.

Object: Can hold multiple values (properties), and can also contain methods (functions) for

working on properties.

An array or object can contain multiple values, all accessed via one variable name. What's

more, those values can themselves be other arrays or objects. This allows you to create quite

complex collections of data.

3. PHP's special data types

As well as scalar and compound types, PHP has 2 special data types that don't fall into the other

categories:

resource :Used to access an external resource (for example, a file handle or database

connection) .

null :Can only contain the value null, which means "no value".

4. Loose typing in PHP

Some languages, such as Java, are strongly typed: once you've created a variable, you can't

change the type of data stored in it. PHP, in contrast, is loosely typed: you can change a

variable's data type at any time.

In the following PHP example, $x starts off by holding integer data (3). The next line appends

the string "hello" to the data using the concatenation operator, which changes $x's value to

"3hello" (a string data type). Finally, 5.67 is assigned to $x, changing its data type to a float:

$x = 3;

$x .= "hello";

$x = 5.67;

Hex and Octal digits: Hex is denoted by /X or /x and octal digits denoted by /0.

Eg: \023 and \x23 .The first one is octal 23, the second is hex 23.

5. Finding out the data type of a value

You can check a value's data type using one of the following PHP functions:

is_int( value )

Returns true if value is an integer, false otherwise

is_float( value )

Returns true if value is a float, false otherwise

is_string( value )

Returns true if value is a string, false otherwise

is_unicode( value )

Returns true if value is a Unicode string, false otherwise

is_binary( value )

Returns true if value is a binary string, false otherwise

is_bool( value )

Returns true if value is a Boolean, false otherwise

is_array( value )

Returns true if value is an array, false otherwise

is_object( value )

Returns true if value is an object, false otherwise

is_resource( value )

Returns true if value is a resource, false otherwise

is_null( value )

Returns true if value is null, false otherwise

is_unicode() and is_binary() are only available in PHP 6 and later.

For example, the following code displays 1 (true):

$x = 3.14;

echo is_float( $x );

6. Changing data types with settype()

As you've already seen, you can change a variable's data type simply by assigning a new value

of a different type to the variable. However, sometimes it's a good idea to explicitly set the type

of the data held by a variable. For example, if you're handing data entered by a visitor, or

passing data to another program, then it's good to ensure that the data is of the correct type.

PHP has a function called settype() that converts a variable's value from one data type to

another:

$x = 3.14;

settype( $x, "integer" );

In the above example, $x's data type is changed from float to integer (with the result that $x

ends up containing the value 3).

Be careful when changing data types, since you may end up losing information — for example,

when changing a float (3.14) to an integer (3).

7. Changing data types with casting

If you just want to change a value's type at the time you use the value, then you can use casting.

This merely changes the type of the value that is to be used; the original variable remains

untouched.

To cast a value, place the data type in parentheses before the value at the time you use it:

$x = 3.14;

echo (integer) $x;

The above code displays 3 (3.14 cast to an integer). However, note that $x still contains the

value 3.14 after the cast operation.

You can, if you prefer, use (int) instead of (integer), and (bool) instead of (boolean).

Operators

An operator is any symbol used to perform an operation on a value. Operators can be classified

into three based on the number of operands it is processing.They are

Unary Operator (operates on only one operand)

Binary Operator (operates on two operands)

Ternary Operator (operates on three operands)

Unary Operator

Incrementing/Decrementing Operators

PHP supports specific operators for incrementing and decrementing numbers. These are a short

hand way of expressing the increase or decrease of a value by one:

Operan

dName Sample

Description

++ Post-increment $var++; Returns $var, then increases it by 1.

++ Pre-increment ++$var; Increases $var by 1, then returns it.

-- Post-decrement $var--; Returns $var, then decreases it by 1.

-- Pre-decrement --$var; Decreases $var by 1, the returns it.

Samples:

$x = 1;

$x++; $x would have the value of 2

$x = 4;

print --$x; -- 4 would be outputted, and then $x would be decremented.

Binary Operator

The Assignment Operator(=)

The assignment operator allows you to assign a value to a variable. You can assign strings,

integers, even the results of functions:

$var = "Hi there";

$var = 1;

$var = myfunction();

The Concatenation Operator ( . )

This operator allows you to append one value to another. You can append strings, other

variables or even the results of functions:

$var = "test";

$var2 = "This is a ".$var;

print $var2; -- This would output "This is a test"

You can also use the Assignment Concatenation Operator to append a new value to the value

an existing variable:

$var = "this is a test";

$var .=" of the emergency broadcast system";

print $var; -- This would output "This is a test of the emergency broadcast system"

Arithmetic Operators

Arithmetic Operators in PHP are used to work with numbers. Addition subtraction, division and

multiplication are all supported:

Opera Name Sample Description

nd

+ Addition $var + $var2 Adds the two values together

- Subtraction $var - $var2Subtracts the second value from the

first.

* Multiplication $var * $var2Multiplies the two values by each

other.

/ Division $var/$var2 Divides the first value by the second.

% Modulus $var%$var2Returns the remainder of the first

value divided by the second.

Modulus operator is used to find the remainder after division

Comparison Operators

Comparison Operators allow you to test things like whether one number value is larger, smaller

or equal to another. Unlike expressions with Arithmetic Operators (which return a value), those

with Comparison Operators evaluate to either TRUE or FALSE and are frequently used in

conditional statements:

Operan

dName Sample

Description

== Equal to $var == $var2Is true if the first value is equivalent to

the second.

!= Not equal to $var != $var2Is true if the first value is not equal to

the second.

< Less than $var < $var2Is true if the first value is less than the

second.

> Greater than $var > $var2Is true if the first value is greater than

the second.

<= Less than or equal $var <= $var2Is true if the first value is less than or

equal to the second.

>=Greater than or

equal$var >= $var2

Is true if the first value is greater than

or equal to the second.

The Equal and Not-Equal To operators are also used to evaluate whether non-numerical values

are equal to each other.

This script how you can use a conditional statement to test whether or not the entered password

is the same as the stored one:

<?php

$storedpassword = "mypassword";

$enteredpassword = "mypassword";

if ($storedpassword == $enteredpassword) {

print "The entered password was correct!";

}else {

print "The entered password was wrong!";

}

?>

In addition to the comparision operators listed above, PHP4 has added two new ones that not

only allow you see if two values are equal, but also check to see if they are of the same type.

Operan

dName Sample

Description

=== Identical $var === $var2 Is true if the first value is equivalent to

the second and both are the same type.

!== Not identical to $var !== $var2

Is true if the first value is not equal to

the second or they are not the same

type

Logical Operators

<?php

$storedusername = "user";

$enteredusername = "user";

$storedpassword = "mypassword";

$enteredpassword = "mypassword";

if ($storedusername == $enteredusername AND $storedpassword == $enteredpassword)

{

print "The entered username and password were correct!";

} else {

print "The entered username and password were wrong!";

}

?>

The "AND" between the two separate conditions tells the script that both must be true for the

entire statement to be considered true. If both are true, then "The entered username and

password were correct!" would be printed.

PHP supports several different Logical Operators:

Operan Name Sample Description

d

AND And $var AND $var2 Is true if both values are true.

OR Or $var OR $var2 Is true if either value is true.

XOR Xor $var XOR $var2 Is true if either value is true, but not both.

&& And $var && $var2 Is true if both values are true.

|| Or $var || $var2 Is true if either value is true.

! Not !$varIs true if the value is not true (ex. if the

variable doesnt exist).

Operator Precedence

Take a look at the following:

$x = 9 + 1 * 10

Because we read left to right, you might assume that $x equals 100 (Nine plus one, times 10,

equals 100); however, because of operator precedence, you would be wrong. The multiplication

operator has higher precedence than the addition operator, so that calculation would be

performed first: One times 10, plus nine, equals 19.

The same rules of precedence apply to Operators in PHP. Take a look at the below chart to get

an idea of how various operators rank. Operators listed in the same row have equal precedence.

Highest Precedence * / %

+ - .

< <= > >=

&&

||

And

Xor

Lowest precedence or

You can also force precedence by using parentheses:

$x = (9 + 1) * 10

Since the first part of the above equation is surrounded, it would be calculated first, and $x

would equal 100.

Ternary Operator

The ternary operator is a shorthand (albeit very hard to read) way of doing if statements.

<?php

$agestr = ($age < 16) ? 'child' : 'adult';

echo $agestr ;

?>

8.

Constants

Via define() directive, like define ("MYCONSTANT", 100);

Octal and hex numbers

PHP Interpreter treats numbers beginning with 0 as octal. \023 and \x23. The first one is octal

23, the second is hex 23.

<?php $str = ‘Hello,

there.\nHow are you?\nThanks for visiting fyicenter’; print $str; ?>

Because inside the single quotes the \n character is not interpreted as newline, just as a sequence

of two characters - \ and n.

echo vs print

echo is the most primitive of them, and just outputs the contents following the construct

to the screen. print is also a construct (so parentheses are optional when calling it), but it

returns TRUE on successful output and FALSE if it was unable to print out the string.

However, you can pass multiple parameters to echo, like:

<?php echo 'Welcome ', 'to', ' ', 'fyicenter!'; ?>

and it will output the string "Welcome to fyicenter!" print does not take multiple

parameters. It is also generally argued that echo is faster, but usually the speed advantage

is negligible, and might not be there for future versions of PHP. printf is a function, not a

construct, and allows such advantages as formatted output, but it’s the slowest way to

print out data out of echo, print and printf.

Operators

Control Structures and Control Loops

Control Structures allow a script to react differently depending on what has already occurred, or

based on user input, and allow the graceful handling of repetitive tasks.

In PHP, there are two primary types of Control Structures: Conditional Statements and Control

Loops.

Conditional Statements

Conditional Statements allow you to branch the path of execution in a script based on whether a

single, or multiple conditions, evaluate to true or false.

If Statements

If Statements always begin with "if", followed by a condition surrounded in parentheses. If the

condition evaluates to true, then the statement or statements immediately following the condition

will be executed.

<?php

$x=1;

if ($x == 1) print '$x is equal to 1';

?>

This example illustrates the simplest kind of If Statement. In this case, had the condition been

false, nothing would have occurred and you would have seen a blank browser window when the

script was run.

When you have more than one statement to be executed within a control structure, it's necessary

to surround them with brackets:

<?php

$x=1;

if ($x == 1) {

print '$x is equal to 1';

$x++;

print 'now $x is equal to 2';

}

?>

Keep in mind that the positioning of the elements does not affect the execution of the script. All

of the example arrangements below are perfectly valid not only for If Statements, but for every

form of control loop.

if ($x == 1) print '$x is equal to 1';

if ($x == 1)

print '$x is equal to 1';

if ($x == 1) { print '$x is equal to 1'; }

if ($x == 1) {

print '$x is equal to 1';

}

You can also include multiple conditions within parentheses. For the nested statements to

execute, all of the conditions must evaluate to true.

<?php

$x=1;

if ($x == 1 OR $x == 2) print '$x is equal to 1 (or maybe 2)';

?>

Else Statements

As the name implies, Else Statements allow you to do something else if the condition within an

If Statement evaluated to false:

<?php

$x=1;

if ($x == 2) {

print '$x is equal to 2';

} else {

print '$x is equal to 1';

}

?>

Else If Statements

Thus far, we have been able to respond to one condition, and do something if that condition is

not true. For evaluating multiple conditions you could use Else If Statements .

A combination of If and Else Statements, Else If Statements are evaluated sequentially if the

condition within the If Statement is false. When a condition within an Else If Statement evaluates

to true, the nested statements are parsed, the script stops executing the entire If/Else if/Else

Structure. The rest of the script proceeds to be parsed.

Take a look at the following example:

<?php

$x=1;

if ($x == 2) {

print '$x is equal to 2';

} else if ($x == 1) {

print '$x is equal to 1';

} else {

print '$x does not equal 2 or 1';

}

?>

The final else statement can be left off if you do not want anything to happen if none of the If or

Else If Statements are true:

<?php

$x=0;

if ($x == 2) {

print '$x is equal to 2';

} else if ($x == 1) {

print '$x is equal to 1';

}

?>

In this case, since neither the condition within the If or Else if Conditions are true, and no Else

Statement was provided, nothing would be outputted to the browser.

Switches

Switches are a good alternative to If/Else if/Else Statements in situations where you want to

check multiple values against a single variable or condition. This is the basic syntax:

<?php

$var = "yes";

switch ($var) {

case "yes":

print '$var is equal to yes';

break;

case "no":

print '$var is equal to no';

break;

}

?>

After running this code snippet, much of what is here will probably make sense to you. In the

first line of the switch statement, we have the identifier "switch" followed by a variable

surrounded by parenthesis. Each case includes a possible value for the variable.

Switches execute a little differently than If/Else if/Else statements. Once a case value matches

the value of the switch expression, every following statement is executed, including those

following other cases.

To prevent this from happening, a break statement is used. "Break;" ends the execution of the

switch statement, and lets the script continue execution; it can also be used in while or for loops.

Optionally, you may also include a special case called "default". This case works much like and

Else Statement, and will execute if all the other cases are found to be false. This case should be

the very last one you include.

<?php

$var = "yes";

switch ($var) {

case "maybe":

print '$var is equal to yes';

break;

case "no":

print '$var is equal to no';

break;

default:

print 'none of the other two cases were true, so this sentance will be printed

out instead.';

}

?>

Similar to the Break Statement is the Exit Statement. Exit is particularly useful in situations

where you run into what would be considered a "fatal error" (for example, if the user had entered

a password that was incorrect) or any other time you needed to end the execution of a script

before it naturally terminated.

<?php

$var = "yes";

switch ($var) {

case "yes":

print '$var is equal to yes';

exit;

case "no":

print '$var is equal to no';

break;

}

print "this will not be printed, because the script will have terminate before this

line is reached";

?>

Unlike break, exit may be used anywhere in your scripts, inside or outside of control structures.

Control Loops

Frequently in PHP there are instances where you need to perform repetitive tasks, such as

formatting data pulled from a database, sending out emails to a mailing list, or cycling through

the contents of an array. Control Loops allow you to perform these tasks almost effortlessly.

While Loops

The statements nested within the loop will execute as long as the condition within the

parentheses evaluates to true. Since the validity of the condition is checked before the loop is

executed, if the condition is false, then the statements within the loop will not be executed at all.

<?php

$x=1;

while ($x <=10) {

print "$x<br>";

$x++;

}

?>

When you run this snippet, you will see the numbers 1 through 10 printed on your screen.

Do...While Loops

Do...While Loops are similar to While Loops. The primary difference in how these work is that

the validity of the condition in a Do...While Loop is tested after the loop has itinerated once.

<?php

$x=11;

do {

print "$x<br>";

$x++;

} while ($x <=10);?>

In the example above, $x would be printed out one time, and then the execution of the loop

would end, because $x is greater than 10.

For Loops

For Loops take three expressions separated by semi-colons. The first expression is only executed

one time, when the loop initializes. The next expression is a condition that is checked each time

the loop itinerates. Once the condition is false, the loop will stop executing. The final expression

will be executed each time the loop iterates after the nested statements have been parsed.

<?php

for($x=1; $x<=10; $x++) {

print "$x<br>";

}

?>

Typically, it's best to use a For Loop in situations where you know how many elements you

will be cycling through.

The Foreach Loop

This new loop was introduced in PHP version 4. Its used exclusively for looping through

elements of an array, allowing you to easily print out or perform operations on elements

within an array.

<?php

$Array = array();

$Array[]="http://www.yahoo.com/";

$Array[]="http://www.internet.com";

$Array[]="http://www.google.com";

$Array[]="http://www.cnn.com/";

$Array[]="http://www.php.net/";

foreach($Array as $key => $value) {

print "$key: $value<br>";

}

?>

The loop advances an internal pointer through each row of the array, assigns the key and the

value to variables, and then prints out one or both of them until the end of the array is reached.

Array

Arrays

PHP arrays are extremely flexible.They allow numeric, auto-incremented keys, alphanumeric

keys or a mix of both, and are capable of storing practically any value, including other

arrays,with over seventy functions for manipulating them.All arrays are ordered collections of

items, called elements. Each element has a value, and is identified by a key that is unique to the

array it belongs to.Keys can be either integer numbers or strings of arbitrary length.

Arrays are created one of two ways. The first is by explicitly calling the array() construct, which

can be passed a series of values and, optionally, keys.

$a = array (10, 20, 30);

$a = array (’a’ => 10, ’b’ => 20, ’cee’ => 30);

$a = array (5 => 1, 3 => 2, 1 => 3,);

$a = array();

A second method of accessing arrays is bymeans of the array operator ([]):

eg:

<?php

$x[]=10;

$x[]=2;

echo $x[0]." ".$x[1]; //output will be 10 2

?>

PHP provides two functions that can be used to outputa variable’s value recursively: print_r()

and var_dump(). They differ in a few key points:

• While both functions recursively print out the contents of composite value,

only var_dump() outputs the data types of each value

• Only var_dump() is capable of outputting the value of more than one variable

at the same time

• Only print_r can return its output as a string, as opposed to writing it to the

script’s standard output

eg:

<?php

$x[]=10;

$x[]=2;

print_r($x); //output will be Array ( [0] => 10 [1] => 2 )

?

<?php

$x[]=10;

$x[]=2;

var_dump($x); //output will be array(2) { [0]=> int(10) [1]=> int(2) }

?>

<?php

$x[]=10;

$x[]=2;

$y=array('c','d');

var_dump($x,$y);

?>

output will be array(2) { [0]=> int(10) [1]=> int(2) } array(2) { [0]=> string(1) "c" [1]=>

string(1) "d" }

Enumerative vs. Associative

Arrays can be roughly divided in two categories: enumerative and associative. Enumerative

arrays are indexed using only numerical indexes, while associative arrays allow the association

of an arbitrary key to every element.

Multi-dimensional Arrays

To create multi-dimensional arrays, we simply assign an array as the value for an array element.

Array Functions

in_array() to determine whether an element with a given value exists in an array

unset() to delete an element from the array

array_flip() inverts the value of each element of an array with its key

array_reverse() inverts the order of the array’s elements

sort() sorts an array based on its values.But effectively destroys all the keys in

the array and renumbers

its elements starting from zero

asort() sorts an array maintain key association

Functions

Defining a function

To create a new function, we simply use the keyword function, followed by an identifier, a pair

of parentheses and braces:

function name() { }

PHP function names are not case-sensitive. As with all identifiers in PHP, the name must consist

only of letters (a-z), numbers and the underscore character, and must not start with a number. To

make your function do something, simply place the code to be execute between the braces, then

call it.

function display()

{

echo "Hello World!";

}

display(); // Displays "Hello World!"

Returning Values

We can specify the return value of your function by using the return keyword:

function hello()

{

return "Hello World"; // No output is shown

}

$txt = hello(); // Assigns the return value "Hello World" to $txt

echo hello(); // Displays "Hello World"

return also allows you to interrupt the execution of a function and exit it even if you don’t want

to return a value:

<?php

$x=0;

function notfive($x)

{

if ($x== 5) {

return; // Nothing else in the function will be processed

}

echo "$x";

}

notfive(5); //no output

notfive(2); //o/p will be 2

?>

Functions can also be declared so that they return by reference; this allows you to return a

variable as the result of the function, instead of a copy (returning a copy is the default for every

data type except objects). Typically, this is used for things like resources (like database

connections).We must return a variable—you cannot return an expression by reference, or use

an empty return statement to force a NULL return value:

eg:

function &query($sql)

{

$result = mysql_query($sql);

return $result;

}

Any variable defined within a function is no longer available after the function has finished

executing. This allows the use of names which may be in use elsewhere without having to

worry about conflicts.

Passing Arguments

Arguments allow you to inject an arbitrary number of values into a function in order to

influence its behaviour.

Eg:

<?php

function add($x,$y)

{

$z=$x+$y;

return $x;

}

echo add(2,3);

?>

Variable-length Argument Lists

The ability to create a function that accepts a variable number of arguments, depending on the

circumstance.PHP provides three built-in functions to handle variable-length argument lists:

func_num_args(), func_get_arg() and func_get_args().

Eg:

<?php

function hello()

{

if (func_num_args() > 0) {

$arg = func_get_arg(0); // The first argument is at position 0

echo "Hello $arg";

} else {

echo "Hello World";

}

}

hello("Reader"); // Displays "Hello Reader"

hello(); // Displays "Hello World"

?>

You can use variable-length argument lists even if you do specify arguments in the function

header. However, this won’t affect the way the variable-length argument list functions behave—

for example, func_num_args() will still return the total number of arguments passed to your

function, both declared and anonymous.

<?php

function countAll($arg1)

{

if (func_num_args() == 0) {

die("You need to specify at least one argument");

} else {

$args = func_get_args(); // Returns an array of arguments

// Remove the defined argument from the beginning

array_shift($args);

$count = strlen ($arg1);

foreach ($args as $arg) {

$count += strlen($arg);

}

}

return $count;

}

echo countAll("foo", "bar", "baz"); // Displays ’9’

?>

Passing Arguments by Reference

Function arguments can also be passed by reference, as opposed to the traditional by-value

method, by prefixing them with the by-reference operator &. This allows your function to affect

external variables.

Example

<?php

function pass_by_reference(&$param) {

array_push($param, 4, 5);

}

$ar = array(1,2,3);

pass_by_reference($ar);

foreach ($ar as $elem) {

print "<br>$elem";

}

?>

The code above prints 1, 2, 3, 4, 5. This is because the array is passed as reference, meaning that

the function (pass_by_reference) doesn't manipulate a copy of the variable passed, but the

actual variable itself.

Passing Arguments by Value

Here the function manipulates a copy of the variable passed,not the actual variable itself.

Example

<?php

function pass_by_value($param) {

array_push($param, 4, 5);

}

$ar = array(1,2,3);

pass_by_value($ar);

foreach ($ar as $elem) {

print "<br>$elem";

}

?>

Different types of sorting

Sorting functions in PHP:

asort()

arsort()

ksort()

krsort()

uksort()

sort()

natsort()

rsort()

Parameter Passing

pass by value vs pass by reference

FORMS

Form: is the area that containing form variables

<form name=”f1” method=” ” action=' '> </form>

Attributes of form tag:

method: contains the HTTP methods for form processing. HTTP includes two methods to

achieve different goals. They are GET and POST.

GET vs POST

GET POST

1. The GET is used when the result of a request does

not make any persistent changes.

2. It uses the collected data to find the resource.

3. Small amount of limited size data can pass

through URL Maximum 1024 characters.

4. The name and value used in the form will display

on the address bar proceeded by URL. So it is not

secure.

5. Used to pass small amount of less sensitive data.

1. POST is used when the result of a request has

persistent side effect such as adding a row to database.

2. POST creates the resource needed.

3. Large amount of data can be passed through URL.

4. The name and value used in form is passed through

invisible STD I/P. So user can't see the passed

information. So it is secure.

5. Used to pass large amount of sensitive data.

6. GET call moves within the page Eg: exp

pagination, url calling etc.

6. POST call moves from one page to another.

Action: when the form is submitted content is sent to another file. The name of that file is

specified using action.

Different types of forms

Text Field: <input type=”text” name=”txtfld” size=25/>

Text area: <textarea name="textarea"></txtarea>

Password: <input type=”password” name=”psswdfld” size=25/>

Hidden Field: <input type="hidden" name="hiddenField" />

Check box: <input type="checkbox" name="chk" id="che" value="1" />

Radio Button: <input type="radio" name="radiobuttonname" value=”1”/>

Radio Button group: <input type="radio" name="male" value="1" /> <input type="radio"

name="female" value="0" />

List: <select name="select"> <option>abc</option> <option>def</option> </select>

Submit Button: <input name="Submitbutt" type="submit" id="Submitbutt"

value="Submit" />

If you don't want to use the Submit button to submit a form, you can use normal hyper links to

submit a form. But you need to use some JavaScript code in the URL of the link. For

example:<a href="javascript: document.myform.submit();">Submit Me</a> or In the Java

Script code, we can call the document.form.submit() function to submit the form. For example:

<input type=button value="Save" onClick="document.form.submit()">

Reset button: <input name="resetbutt" type="reset" id="resetbutt" value="Reset" />

Button: <input name="backbutton" type="button" id="backbutton" value="Button" />

Field Set: <fieldset> <legend> Introuduction </legend> </fieldset>

File operations

Uploading files

Once the Web server received the uploaded file, it will call the PHP script specified in the form

action attribute to process them. This receiving PHP script can get the uploaded file information

through the predefined array called $_FILES. Uploaded file information is organized in

$_FILES as a two-dimensional array as:

$_FILES[$fieldName]['name'] - The Original file name on the browser system.

$_FILES[$fieldName]['type'] - The file type determined by the browser.

$_FILES[$fieldName]['size'] - The Number of bytes of the file content.

$_FILES[$fieldName]['tmp_name'] - The temporary filename of the file in which the

uploaded file was stored on the server.

$_FILES[$fieldName]['error'] - The error code associated with this file upload.

The $fieldName is the name used in the <INPUT TYPE=FILE, NAME=fieldName>.

How to store the uploaded file to the final location?

move_uploaded_file ( string filename, string destination)

This function checks to ensure that the file designated by filename is a valid upload file

(meaning that it was uploaded via PHP's HTTP POST upload mechanism). If the file is valid, it

will be moved to the filename given by destination. If filename is not a valid upload file, then

no action will occur, and move_uploaded_file() will return FALSE. If filename is a valid upload

file, but cannot be moved for some reason, no action will occur, and move_uploaded_file() will

return FALSE. Additionally, a warning will be issued.

Directory Operations

DATE and Time functions

adddate()

This is used to perform operations on a value of datatype datetime

Syntax

adddate(expression,interval indays/month/year)

Examples

select adddate('2009-10-11',interval 2 year);

O/P : 2011-10-11

select adddate('2009-10-11',interval 3 month);

O/P : 2010-01-11

select adddate('2009-10-11',interval 3 day);

O/P : 2009-10-14

curdate()

This is used to get the current date

Syntax

curdate()

Examples

select curdate();

curtime()

This is used to get the current time in hh:mm:ss

Syntax

curtime()

Examples

select curtime();

O/P : 23:28:46

date()

This is used to extract date from a datetime value

Syntax

date('datetime value')

Example

select date('2007-12-23 22:10:12');

O/P : 2007-12-23

datediff()

This is used to find how many days are there to reach the first date from the second date

Syntax

datediff('expression1','expression2')

Example

select datediff('2009-10-17','2009-10-11');

O/P : 6

date_sub()

This is used to substract specified value in days/month/year from the given date

Syntax

date_sub('expression1',interval in days/month/year )

Example

select date_sub('2009-10-17',interval 6 day);

O/P : 2009-10-11

For further reference check http://dev.mysql.com/doc/refman/5.1/en/date-and-time-

functions.html

The number of days between two given dates using PHP

Simple arithmetic:

$date1 = date('Y-m-d');

$date2 = '2006-07-01';

$days = (strtotime() - strtotime()) / (60 * 60 * 24);

echo "Number of days since '2006-07-01': $days";

SELECT CURDATE();

SELECT CURRENT_DATE();

SELECT CURTIME();

SELECT CURRENT_TIME();

How can we know the number of days between two given dates using MySQL?

Use DATEDIFF()

SELECT DATEDIFF(NOW(),'2006-07-01');

MYSQL

MySQL SET function can take zero or more values, but at the maximum it can take 64 values.

DESCRIBE table_name;

How can I load data from a text file into a table?

The MySQL provides a LOAD DATA INFILE command. You can load data from a file.

Great tool but you need to make sure that:

a) Data must be delimited

b) Data fields must match table columns correctly

ALTER TABLE table_name CHANGE old_colm_name new_colm_name

ALTER TABLE table_name CHANGE colm_name same_colm_name [new data type]

Databases

What is the maximum length of a table name, a database name, or a field name in

MySQL?

Database name: 64 characters

Table name: 64 characters

Column name: 64 characters

What is maximum size of a database in mysql?If the operating system or filesystem places a

limit on the number of files in a directory,

MySQL is bound by that constraint. The efficiency of the operating system in handling

large numbers of files in a directory can place a practical limit on the number of tables in

a database. If the time required to open a file in the directory increases significantly as the

number of files increases, database performance can be adversely affected.

The amount of available disk space limits the number of tables.

MySQL 3.22 had a 4GB (4 gigabyte) limit on table size. With the MyISAM storage

engine in MySQL 3.23, the maximum table size was increased to 65536 terabytes (2567

– 1 bytes). With this larger allowed table size, the maximum effective table size for

MySQL databases is usually determined by operating system constraints on file sizes, not

by MySQL internal limits.

The InnoDB storage engine maintains InnoDB tables within a tablespace that can be

created from several files. This allows a table to exceed the maximum individual file size.

The tablespace can include raw disk partitions, which allows extremely large tables. The

maximum tablespace size is 64TB.

The following table lists some examples of operating system file-size limits. This is only

a rough guide and is not intended to be definitive. For the most up-to-date information, be

sure to check the documentation specific to your operating system.

Operating System File-size Limit

Linux 2.2-Intel 32-bit 2GB (LFS: 4GB)

Linux 2.4+ (using ext3 filesystem) 4TB

Solaris 9/10 16TB

NetWare w/NSS filesystem 8TB

Win32 w/ FAT/FAT32 2GB/4GB

Win32 w/ NTFS 2TB (possibly larger)

MacOS X w/ HFS+ 2TB

normalization

The normalization process involves getting our data to conform to three progressive

normal forms, and a higher level of normalization cannot be achieved until the previous

levels have been achieved (there are actually five normal forms, but the last two are

mainly academic and will not be discussed).

First Normal Form

The First Normal Form (or 1NF) involves removal of redundant data from horizontal

rows. We want to ensure that there is no duplication of data in a given row, and that every

column stores the least amount of information possible (making the field atomic).

Second Normal Form

Where the First Normal Form deals with redundancy of data across a horizontal row,

Second Normal Form (or 2NF) deals with redundancy of data in vertical columns. As

stated earlier, the normal forms are progressive, so to achieve Second Normal Form, your

tables must already be in First Normal Form.

Third Normal Form

I have a confession to make; I do not often use Third Normal Form. In Third Normal

Form we are looking for data in our tables that is not fully dependant on the primary key,

but dependant on another value in the table

VARCHAR vs CHAR vs TEXT

CHAR is a fixed length data type. CHAR(n) will take n characters of storage even if you

enter less than n characters to that column. For example, "Hello!" will be stored as

"Hello! " in CHAR(10) column.

VARCHAR is a variable length data type. VARCHAR(n) will take only the required

storage for the actual number of characters entered to that column. For example, "Hello!"

will be stored as "Hello!" in VARCHAR(10) column.

Aggregate functions

GROUP BY vs ORDER BY

To sort a result, use an ORDER BY clause.

The most general way to satisfy a GROUP BY clause is to scan the whole table and

create a new temporary table where all rows from each group are consecutive, and then

use this temporary table to discover groups and apply aggregate functions (if any).

ORDER BY [col1],[col2],...[coln]; Tells DBMS according to what columns it should sort

the result. If two rows will hawe the same value in col1 it will try to sort them according

to col2 and so on.

GROUP BY [col1],[col2],...[coln]; Tells DBMS to group (aggregate) results with same

value of column col1. You can use COUNT(col1), SUM(col1), AVG(col1) with it, if you

want to count all items in group, sum all values or view average.

JOIN

DROP vs TRUNCATE

DROP TABLE table_name - This will delete the table and its data.

TRUNCATE TABLE table_name - This will delete the data of the table, but not the table

definition.

REPAIR

The syntex for repairing a mysql table is:

REPAIR TABLE tablename

REPAIR TABLE tablename QUICK

REPAIR TABLE tablename EXTENDED

This command will repair the table specified.

If QUICK is given, MySQL will do a repair of only the index tree.

If EXTENDED is given, it will create index row by row.

MYSQL engine architecture.

What are the different tables present in MySQL? Which type of table is generated

when we are creating a table in the following syntax: create table employee(eno

int(2),ename varchar(10))?

Total 5 types of tables we can create

1. MyISAM

2. Heap

3. Merge

4. INNO DB

5. ISAM

MyISAM is the default storage engine as of MySQL 3.23. When you fire the above

create query MySQL will create a MyISAM table.

In MySQL, the default table type is MyISAM.

Each MyISAM table is stored on disk in three files. The files have names that begin with

the table name and have an extension to indicate the file type.

The '.frm' file stores the table definition.

The data file has a '.MYD' (MYData) extension.

The index file has a '.MYI' (MYIndex) extension,

PHPMyadmin

PHP interface to MYSQL

We can create MySQL database with the use of mysql_create_db($databaseName) to

create a database.

If you want to create a table, you can run the CREATE TABLE statement as shown in the

following sample script:

<?php

include "mysql_connection.php";

$sql = "CREATE TABLE fyi_links ("

. " id INTEGER NOT NULL"

. ", url VARCHAR(80) NOT NULL"

. ", notes VARCHAR(1024)"

. ", counts INTEGER"

. ", time TIMESTAMP DEFAULT sysdate()"

. ")";

if (mysql_query($sql, $con)) {

print("Table fyi_links created.\n");

} else {

print("Table creation failed.\n");

}

mysql_close($con);

?>

Remember that mysql_query() returns TRUE/FALSE on CREATE statements. If you run

this script, you will get something like this:

Table fyi_links created.

mysql_fetch methods

MySQL fetch object will collect first single matching record where mysql_fetch_array

will collect all matching records from the table in an array

.

mysql_fetch_array() -> Fetch a result row as a combination of associative array and

regular array.

mysql_fetch_object() -> Fetch a result row as an object.

mysql_fetch_row() -> Fetch a result set as a regular array().

Answer 2:

The difference between mysql_fetch_row() and mysql_fetch_array() is that the first

returns the results in a numeric array ($row[0], $row[1], etc.), while the latter returns a

the results an array containing both numeric and associative keys ($row['name'],

$row['email'], etc.). mysql_fetch_object() returns an object ($row->name, $row->email,

etc.).

mysql_fetch_array - Fetch a result row as an associative array and a numeric array.

mysql_fetch_object - Returns an object with properties that correspond to the fetched row

and moves the internal data pointer ahead. Returns an object with properties that

correspond to the fetched row, or FALSE if there are no more rows

mysql_fetch_row() - Fetches one row of data from the result associated with the specified

result identifier. The row is returned as an array. Each result column is stored in an array

offset, starting at offset 0.

mysql_fetch_assoc - Fetch a result row as an associative array

SESSIONS

A session is a logical object created by the PHP engine to allow you to preserve data

across subsequent HTTP requests.

There is only one session object available to your PHP scripts at any time. Data saved to the

session by a script can be retrieved by the same script or another script when

requested from the same visitor.

Sessions are commonly used to store temporary data to allow multiple PHP pages to offer

a complete functional transaction for the same visitor.

unlink() is a function for file system handling. It will simply delete the file in context.

unset() is a function for variable management. It will make a variable undefined.

register the variables into a session?

session_register($session_var);

$_SESSION['var'] = 'value';

session_unregister() - Unregister a global variable from the current session

session_unset() - Free all session variables

Session depends on browser. If browser is closed then session is lost. The session data

will be deleted after session time out. If connection is lost and you recreate connection,

then session will continue in the browser.

The session support can be turned on automatically at the site level, or manually in each

PHP page script:

Turning on session support automatically at the site level: Set session.auto_start =

•

1 in php.ini.

Turning on session support manually in each page script: Call session_start()

•

funtion.

COKKIES

Persistent Cookie

A persistent cookie is a cookie which is stored in a cookie file permanently on the browser's

computer. By default, cookies are created as temporary cookies which stored only in the

browser's memory. When the browser is closed, temporary cookies will be erased. You should

decide when to use temporary cookies and when to use persistent cookies based on their

differences:

Temporary cookies can not be used for tracking long-term information.

Persistent cookies can be used for tracking long-term information.

Temporary cookies are safer because no programs other than the browser can

access them.

Persistent cookies are less secure because users can open cookie files see the

cookie values

How to set cookies?

setcookie('variable','value','time')

;

variable - name of the cookie variable

value - value of the cookie variable

time - expiry time

Example: setcookie('Test',$i,time()+3600);

Test - cookie variable name

$i - value of the variable 'Test'

time()+3600 - denotes that the cookie will expire after an one hour

How to reset/destroy a cookie

Reset a cookie by specifying expire time in the past:

Example: setcookie('Test',$i,time()-3600); // already expired time

Reset a cookie by specifying its name only

Example: setcookie('Test');

REDIRECTTION from one page to another

Here are the possible ways of php page redirection.

1. Using Java script:

'; echo 'window.location.href="'.$filename.'";'; echo ''; echo ''; echo ''; echo ''; } }

redirect('http://maosjb.com'); ?>

2. Using php function: header("Location:http://maosjb.com ");

void header ( string string [, bool replace [, int http_response_code]])

What type of headers have to be added in the mail function to attach a file?

$boundary = '--' . md5( uniqid ( rand() ) );

$headers = "From: \"Me\"\n";

$headers .= "MIME-Version: 1.0\n";

$headers .= "Content-Type: multipart/mixed; boundary=\"$boundary\"";

PHP. ini file

PHP INI Settings

Setting up the extensions

To set up the extensions point PHP to the directory that holds the extension libraries and you

need to uncomment the desired extensions.

Point PHP to the correct directory:

Set extension_dir in php.ini to "C:\PHP\ext" (extension_dir = "C:\PHP\ext")

Uncomment the ones you want to use.

It’s important to be sure that php_mysql.dll extension is uncommented (for PHP 5 or

newer).

Extensions

extension=php_gd2.dll

extension=php_mssql.dll

extension=php_mysql.dll

File Uploading

file_uploads = On ;If you want users to be able to upload files using PHP

scripts.

upload_tmp_dir = "C:\TEMP" ;Path must be in a folder writeable from all websites.

upload_max_filesize = 32M ;Max file size that can be uploaded.

Other Settings

short_open_tag

This is on by default, but using short tags (<?) is bad form. Turn it off and don’t utilize it. (Edit)

There are two reasons for this. First, and the more rare reason, is that it could create problems

with XML parsing. If you ever have the need to embed PHP in XML (as I did once), you may

run into this. This is rare, but possibe. Second, and more common, is that if you ever change

hosts, or start using a host that configures PHP for you, they may disable the short tags by

default. This could leave you scrambling for a fix for your code. Changing 20,000 <? into <?

php can take a long time (I’ve done it; it can be a pain).

register_globals

The register_globals setting controls how you access form, server, and environment variables.

By default this variable is set to Off, requiring you to use special arrays to access these

variables. Those familiar with older versions of PHP will be used to an environment in which

the register_globals variable is effectively On; with this setting, you can access form, server and

environment variables simply by name.

display_errors and display_startup_errors

These two settings control whether PHP should display errors in the browser or be silent. It is

recommended that you turn these two settings Off during production so that you don't

accidentally display sensitive information about your Web site. This is especially true for

dynamic Web sites that send user names and passwords to access a database.

special set of tags do in PHP. What does a special set of tags <?= and ?> do in PHP?

The output is displayed directly to the browser.

Errors in PHP

Here are three basic types of runtime errors in PHP:

1. Notices: These are trivial, non-critical errors that PHP encounters while executing a script -

for example, accessing a variable that has not yet been defined. By default, such errors are not

displayed to the user at all - although you can change this default behavior.

2. Warnings: These are more serious errors - for example, attempting to include() a file which

does not exist. By default, these errors are displayed to the user, but they do not result in script

termination.

3. Fatal errors: These are critical errors - for example, instantiating an object of a non- existent

class, or calling a non-existent function. These errors cause the immediate termination of the

script, and PHP's default behavior is to display them to the user when they take place.

Internally, these variations are represented by twelve different error types

Encryption in PHP

urlencode() returns the URL encoded version of the given string. URL coding converts special

characters into % signs followed by two hex digits. For example:

urlencode("10.00%") will return "10%2E00%25". URL encoded strings are safe to be used as

part of URLs. urldecode() returns the URL decoded version of the given string.

Anwser 2:

string urlencode(str) - Returns the URL encoded version of the input string. String values to be

used in URL query string need to be URL encoded. In the URL encoded version: Alphanumeric

characters are maintained as is.Space characters are converted to "+" characters.

Other non-alphanumeric characters are converted "%" followed by two hex digits representing

the converted character.

string urldecode(str) - Returns the original string of the input URL encoded string.

For example:

$discount ="10.00%";

$url = "http://domain.com/submit.php?disc=".urlencode($discount);

echo $url;

You will get "http://domain.com/submit.php?disc=10%2E00%25".

Answer1

You can encrypt a password with the following Mysql>SET

PASSWORD=PASSWORD("Password");

Answer2

You can use the MySQL PASSWORD() function to encrypt username and password. For

example,

INSERT into user (password, ...) VALUES (PASSWORD($password”)), ...);

How To Protect Special Characters in Query String?

If you want to include special characters like spaces in the query string, you need to

protect them by applying the urlencode() translation function. The script below shows

how to use urlencode():

<?php

print("<html>");

print("<p>Please click the links below"

." to submit comments about FYICenter.com:</p>");

$comment = 'I want to say: "It\'s a good site! :->"';

$comment = urlencode($comment);

print("<p>"

."<a href=\"processing_forms.php?name=Guest&comment=$comment\">"

."It's an excellent site!</a></p>");

$comment = 'This visitor said: "It\'s an average site! :-("';

$comment = urlencode($comment);

print("<p>"

.'<a href="processing_forms.php?'.$comment.'">'

."It's an average site.</a></p>");

print("</html>");

?>

AES_ENCRYPT() and AES_DECRYPT()

AES_ENCRYPT(str, key_str)

AES_DECRYPT(crypt_str, key_str)

CRYPT()

MD5()

OOP concepts in PHP

Class

A class is user defined data type that contains attributes or data members; and methods which

work on the data members. To create a class, you need to use the keyword class followed by the

name of the class. The name of the class should be meaningful to exist within the system .The

body of the class is placed between two curly brackets within which you declare class data

members/variables and class methods.

class Customer

{

private $first_name, $last_name;

public function setData($first_name, $last_name)

{ $this->first_name = $first_name;

$this->last_name = $last_name;

}

  public function printData()

{ echo $this->first_name . " : " . $this->last_name;

}

}

Definition of an Object

An object is a living instance of a class. This means that an object is created from the definition

of the class and is loaded in memory.

Creating Objects in PHP5 Class

To create an object of a PHP5 class we use the keyword new. Below is the syntax style of how

to create objects in PHP5:

$obj_name = new ClassName();

In the above syntax style, $obj_name is a variable in PHP. ‘new’ is the keyword which is

responsible for creating a new instance of ClassName.

class Customer

{

private $first_name, $last_name;

public function getData($first_name, $last_name)

{ $this->first_name = $first_name;

$this->last_name = $last_name;

}

public function printData()

{ echo $this->first_name . " : " . $this->last_name;

}

}

$c1 = new Customer();

$c2 = new Customer();

In the above example $c1 and $c2 are two objects of the Customer Class. Both these objects are

allocated different blocks in the memory. Look at the diagram below:

Therefore, an object is a living instance of a class. Each object / living instance has its own

memory space that can hold independent data values.

Definition of an class attribute

An attribute is also know as data members and is used to hold data of a class. The data that it

holds are specific to the nature of the class in which it has been defined. For example, a

Customer class would hold data related to a customer, an Order class would hold data related a

an order.

Defining an attribute is as easy as declaring a variable within the body of the class. At the time

of declaring a data member/variable within the body of the class, it is also possible to assign a

default value to the attribute or data member.

Attributes can either be public, private or protected - the default being public. These are called

Access Specifiers.

Access Specifiers

Access specifiers specify the level of access that the outside world (i.e. other class objects,

external functions and global level code) have on the class methods and class data members.

Access specifiers can either be public, private or protected. Access specifiers are used as a key

component of Encapsulation and Data Hiding. By using either of the access specifiers

mentioned above i.e. public, private or protected you can hide or show the internals of your

class to the outside world.

Private

A private access specifier is used to hide the data member or member function to the outside

world. This means that only the class that defines such data member and member functions have

access them. Look at the example below:

class Customer

{

private $name;

public function setName($name)

{ $this->name = $name;

}

public function getName()

{ return $this->name;

}

}

$c = new Customer();

$c->setName("Sunil Bhatia");

echo $c->name; //error, $name cannot be accessed from outside the class

//$name can only be accessed from within the class

echo $c->getName(); //this works, as the methods of the class have access

//to the private data members or methods

In the above example, echo $c->name will give you an error as $name in class Customer has

been declared private and hence only be accessed by its member functions internally. Therefore,

the following line echo $c->getName() will display the name.

Public

A public access specifier provides the least protection to the internal data members and member

functions. A public access specifier allows the outside world to access/modify the data members

directly unlike the private access specifier. Look at the example below:

class Customer

{

public $name;

public function setName($name)

{ $this->name = $name;

}

public function getName()

{ return $this->name;

}

}

$c = new Customer();

$c->setName("Sunil Bhatia");

echo $c->name; // this will work as it is public.

$c->name = "New Name" ; // this does not give an error.

In the above example, echo $c->name will work as it has been declared as public and hence can

be accessed by class member functions and the rest of the script.

Protected

A protected access specifier is mainly used with inheritance. A data member or member

function declared as protected will be accessed by its class and its base class but not from the

outside world (i.e. rest of the script). We can also say that a protected data member is public for

the class that declares it and it’s child class; but is private for the rest of the program (outside

world). Look at the example below:

class Customer

{ protected $name;

public function setName($name)

{ $this->name = $name;

}

public function getName()

{ return $this->name;

}

}

class DiscountCustomer extends Customer

{ private $discount;

public function setData($name, $discount)

{ $this->name = $name; //this is storing $name to the Customer

//class $name variable. This works

// as it is a protected variable

$this->discount = $discount;

}

}

$dc = new DiscountCustomer();

$dc->setData("Sunil Bhatia",10);

echo $dc->name; // this does not work as $name is protected and hence

// only available in Customer and DiscountCustomer class

In the above example, echo $dc->name will not work work $name has been defined as a

protected variable and hence it is only available in Customer and DiscountCustomer class.

Objects as Attributes

In addition to declaring attributes as intrinsic data types (int, string, etc), you can also declare

data members as objects of another class. This is called aggregation in Object Oriented Analysis

and Design (OOAD). Lets look at an example below:

class Customer

{

private $first_name, $last_name;

private $outstanding_amount = 0; //example of default value

public function getData($first_name, $last_name)

{ $this->first_name = $first_name;

$this->last_name = $last_name;

}

public function printData()

{ echo $this->first_name . " : " . $this->last_name;

}

}

class Order

{ private $order_id;

private $customer;

public setCust(Customer $c)

{ $this->customer = $c;

}

}

$c1 = new Customer();

$o1 = new Order();

$o1->setCust($c1); //storing $c1 object in $o1 order object

In the above example setCust() method accepts a Customer type of parameter which is stored

internally in the $customer data member.

The advantage of the above method is that it allows you to change the customer object

independently of the order object. Imagine having to add 3 - 4 new data members to the

Customer object. You only have to modify the Customer object without having the need to

modify the Order Object.

Definition of an class method

A class method/functions is the behavior/functionality of a class i.e. they provide the necessary

code for the class in which it is defined.

Methods act (perform operations) on the data members of the class and can be declared as

private or public. A class method is exactly similar to PHP functions, it’s just that class

functions are declared inside classes and accessed using the -> (arrow operator / dereferencing

operator).

Methods can also be declared as either public, protected or private.

class Customer

{ private $name;

public functionsetName($name)

{ $this->name = $name;

}

}

$c1 = new Customer();

$c1->setName("Sunil Bhatia");

In the above example setName() is the class method of the Customer class. The setName() class

method is responsible for accepting the name of the customer and storing it in the internal data

member i.e. $name.

The reason why you require methods is so that you can perform necessary validations on the

data passed. Let’s re-look at the above example with necessary validation code.

class Customer

{ private $name;

public function setName($name)

{ if(trim($name) != "")

{

$this->name = $name;

return true;

}

Else

{ return false;

}

}

}

$c1 = new Customer();

$c1->setName("Sunil Bhatia");

In the above example the setName() method accepts a customer’s name and validates to check

if $name is blank. If $name is blank the setName() function returns false; otherwise it stores the

$name in the $this->name of the class and returns true.

Need for a Constructor

It is needed as it provides an opportunity for doing necessary setup operations like initializing

class variables, opening database connections or socket connections, etc. In simple terms, it is

needed to setup the object before it can be used.

PHP5 Constructor

In PHP5 a constructor is defined by implementing the __construct() method. This naming style

has been introduced in PHP5. In PHP4, the name of the constructor was the same name as that

of the class. So, for example if you had a class Customer, you would have to implement a

function Customer().

PHP5 to be backward complaint also supports the PHP4 rule. When an object is created, PHP5

searches for __construct() first. If __construct() is not defined it then searches for a method with

the same that of the class. However, if you define both; PHP5 will first search for __construct()

method and execute it if available, otherwise it will execute the same class name function.

Constructor

class Customer

{ public function __construct() {

//code

}

}

Let’s look at a real example:

class Customer {

private $first_name;

private $last_name;

private $outstanding_amount;

public function __construct() {

$first_name = "";

$last_name = "";

$outstanding_amount = 0;

}

public function setData($first_name, $last_name, $outstanding_amount) {

$this->first_name = $first_name;

$this->last_name = $last_name;

$this->outstanding_amount = $outstanding_amount;

}

public function printData() {

echo "Name : " . $first_name . " " . $this->last_name . "\n";

echo "Outstanding Amount : " . $this->outstanding_amount . "\n";

}

}

$c1 = new Customer();

$c1->setData("Sunil","Bhatia",0);

In the above example on line number 26, we create a new object of the Customer class. the

‘new’ operator is responsible for creating the Customer class. At this point PHP5 searches the

Customer class to see if a constructor has been defined. Therefore, it calls the constructor

method i.e. __construct() defined starting from line no 7. The __construct() method sets the

$first_name and $last_name to blank and sets the $outstanding_amount to zero.

Parameterized Constructor or Argument Constructor

A parameterized or argument constructor is a constructor which accepts values in the form of

arguments in the constructor. Unlike other programming languages where overloaded argument

constructors is possible, in PHP5 you cannot overload constructors.

Example:

class Customer {

private $first_name;

private $last_name;

private $outstanding_amount;

public function __construct($first_name, $last_name, $outstanding_amount) {

$this->setData($first_name, $last_name, $outstanding_amount);

}

public function setData($first_name, $last_name, $outstanding_amount) {

$this->first_name = $first_name;

$this->last_name = $last_name;

$this->outstanding_amount = $outstanding_amount;

}

public function printData() {

echo "Name : " . $first_name . " " . $this->last_name . "\n";

echo "Outstanding Amount : " . $this->outstanding_amount . "\n";

}

}

$c1 = new Customer("Sunil","Bhatia",0);

In the above example on line number 24, we create a new object $c1 and pass values “Sunil”,

“Bhatia” and zero to the constructor defined on line number starting 7. The constructor now

takes 3 arguments and stores them in the internal private variable $first_name, $last_name and

$outstanding_amount respectively.

Inheritance

Inheritance is a mechanism where a new class is derived from the existing base class. The

derived class shares/inherit the functionality of the base class. To extend the class behavior

PHP5 have introduced a new keyword called “extends“.

<php

class parent1

{

protected $firstname = 11;

protected $lastname = 23;

}

class children extends parent1

{

function __construct()

{

echo $this->firstname;

echo $this->lastname;

}

}

$a = new children();

?>

1. Interfaces Abstract Classes

1. Abstract Classes

An abstract class is a class that is only partially implemented by the programmer. It may contain

one or more abstract methods. An abstract method is simply a function definition that serves to

tell the programmer that the method must be implemented in a child class.

To create an abstract class we use the code shown in Listing 1:

Listing 1: An Abstract PHP class

<?php

abstract class Weapon

{

private $SerialNumber;

abstract public function fire();

public function __construct($SerialNumber)

{

$this->SerialNumber = $SerialNumber;

}

public function getSerialNumber()

{

return $this->SerialNumber;

}

}

?>

The abstract class in Listing 1 contains some of the methods required for a weapon. The fire()

method however, cannot be implemented because each different weapons use different firing

different mechanisms. The method is therefore declared as abstract, meaning it will be

implemented in a more specific child class.

Because the class is abstract, an instance of it can never be created (remember, it is only a

partial implementation). Instead a child class must be created using inheritance and implement

the fire method in itself. Failure to do so will result in a fatal error. Listing 2 shows a child class

being created from the Abstract Weapon class.

Listing 2: Extending the Abstract Weapons class

<?php

class Gun extends Weapon

{

public function fire()

{

if($this->SafetyOff) {

return $this->CurrentBullet;

}

}

}

class Cannon extends Weapon

{

public function fire()

{

$this->NeedsLoading = true;

return $this->CurrentCanon;

}

?>

An instance of the Cannon and Gun classes can now be created because they now fully

implemented subclasses of weapon.

2. Interfaces

An interface is similar to an abstract class; indeed interfaces occupy the same namespace as

classes and abstract classes. For that reason, you cannot define an interface with the same name

as a class. An interface is a fully abstract class; none of its methods are implemented and instead

of a class sub-classing from it, it is said to implement that interface.

An interface will be used in the database abstraction layer you create. This ensures that every

time you create a class for a particular database, the same API is exposed. When using an

interface, you can then rely on the methods defined for the interface to be part of the class

because, if they are not, PHP will not parse it.

The MySql functions will be used as an example because they are the most commonly used

amongst PHP programmers. The most commonly used functions are:

mysql_connect()

mysql_error()

mysql_errno()

mysql_query()

mysql_fetch_array()

mysql_fetch_row()

mysql_fetch_assoc()

mysql_fetch_object()

mysql_num_rows()

mysql_close()

If all the database class APIs you create can expose the same methods with the same return

types then you can be sure that changing from one database to another, such as from MySql to

Postgre SQL, will be painless. As such, the interface in listing 3 can be determined for your

API.

Listing 3: An Abstracted Database Interface

interface DB

{

public function connect();

public function error();

public function errno();

public static function escape_string($string);

public function query($query);

public function fetch_array($result);

public function fetch_row($result);

public function fetch_assoc($result);

public function fetch_object($result);

public function num_rows($result);

public function close();

}

Any class implementing the interface must define each method that is declared in the interface,

and each method must have at least the parameters identified in their interface definitions. It

may have more parameters as long as they are optional, but it cannot have less

PolyMorphism

Definition: polymorphism describes multiple possible states for a single property .

<?php

class animal {

public $name;

protected function setName($name){

$this->name = $name;

}

public function speak(){

return "No Animal Selected!";

}

}

class dog extends animal {

public function __construct($name){

$this->setName($name);

}

public function speak(){

return "Woof Woof";

}

}

class cat extends animal {

public function __construct($name){

$this->setName($name);

}

public function speak(){

return "I'm In your class, overloading your methods"; // :)

}

}

class human extends animal {

public function __construct($name){

$this->setName($name);

}

public function speak(){

return "Hello, My Name is " . $this->name;

}

}

$animal = new animal(); // Animal

$dog = new dog('rover'); // Dog named Rover

$cat = new cat('garfield'); // Cat named Garfield

$human = new human('fred'); // Human named Fred

// Non-existent animal cannot speak

echo $animal->speak();

// Dog's bark

echo $dog->speak();

// Cat's do nefarious things

echo $cat->speak();

// Human's Introduce themselves

echo $human->speak();

Features and advantages of OBJECT ORIENTED PROGRAMMING?

One of the main advantages of OO programming is its ease of modification; objects can easily

be modified and added to a system there by reducing maintenance costs. OO programming is

also considered to be better at modeling the real world than is procedural programming. It

allows for more complicated and flexible interactions. OO systems are also easier for non-

technical personnel to understand and easier for them to participate in the maintenance and

enhancement of a system because it appeals to natural human cognition patterns. For some

systems, an OO approach can speed development time since many objects are standard across

systems and can be reused. Components that manage dates, shipping, shopping carts, etc. can be

purchased and easily modified for a specific system.

Abstract class vs interfaces

Abstract class: abstract classes are the class where one or more methods are abstract but not

necessarily all method has to be abstract. Abstract methods are the methods, which are declare

in its class but not define. The definition of those methods must be in its

extending class.Interface: Interfaces are one type of class where all the methods are abstract.

That means all the methods only declared but not defined. All the methods must be define by its

implemented class.

polymorphism

Inheritance

What type of inheritance that php supports?In PHP an extended class is always dependent on a

single base class, that is, multiple

inheritance is not supported. Classes are extended using the keyword 'extends'.

access specifiers

scope resolution operator

include vs require vs include_once

Anwser 1:

require_once() and include_once() are both the functions to include and evaluate the

specified file only once. If the specified file is included previous to the present call

occurrence, it will not be done again.

But require() and include() will do it as many times they are asked to do.

Anwser 2:

The include_once() statement includes and evaluates the specified file during the

execution of the script. This is a behavior similar to the include() statement, with the only

difference being that if the code from a file has already been included, it will not be

included again. The major difference between include() and require() is that in failure

include() produces a warning message whereas require() produces a fatal errors.

Anwser 3:

All three are used to an include file into the current page.

If the file is not present, require(), calls a fatal error, while in include() does not.

The include_once() statement includes and evaluates the specified file during the

execution of the script. This is a behavior similar to the include() statement, with the only

difference being that if the code from a file has already been included, it will not be

included again. It des not call a fatal error if file not exists. require_once() does the same

as include_once(), but it calls a fatal error if file not exists.

Anwser 4:

File will not be included more than once. If we want to include a file once only and

further calling of the file will be ignored then we have to use the PHP function

include_once(). This will prevent problems with function redefinitions, variable value

reassignments, etc.

It’s how they handle failures. If the file is not found by require(), it will cause a fatal error

and halt the execution of the script. If the file is not found by include(), a warning will be

issued, but execution will continue.

MAIL

What is meant by MIME?

Answer 1:

MIME is Multipurpose Internet Mail Extensions is an Internet standard for the format of

e-mail. However browsers also uses MIME standard to transmit files. MIME has a header

which is added to a beginning of the data. When browser sees such header it shows the

data as it would be a file (for example image)

Some examples of MIME types:

audio/x-ms-wmp

image/png

aplication/x-shockwave-flash

Answer 2:

Multipurpose Internet Mail Extensions.

WWW's ability to recognize and handle files of different types is largely dependent on

the use of the MIME (Multipurpose Internet Mail Extensions) standard. The standard

provides for a system of registration of file types with information about the applications

needed to process them. This information is incorporated into Web server and browser

software, and enables the automatic recognition and display of registered file types.

What are the functions for IMAP?

imap_body - Read the message body

imap_check - Check current mailbox

imap_delete - Mark a message for deletion from current mailbox

imap_mail - Send an email message

AJAX

Javascript

No. There is no way to send emails directly using JavaScript.

But you can use JavaScript to execute a client side email program send the email using

the "mailto" code. Here is an example:

function myfunction(form)

{

tdata=document.myform.tbox1.value;

location="mailto:mailid@domain.com?subject=...";

return true;

}

CSS

What are the advantages and disadvantages of CASCADE STYLE SHEETS?

External Style Sheets

Advantages

Can control styles for multiple documents at once Classes can be created for use on

multiple HTML element types in many documents Selector and grouping methods can be

used to apply styles under complex contexts

Disadvantages

An extra download is required to import style information for each document The

rendering of the document may be delayed until the external style sheet is loaded

Becomes slightly unwieldy for small quantities of style definitions

Embedded Style Sheets

Advantages

Classes can be created for use on multiple tag types in the document Selector and

grouping methods can be used to apply styles under complex contexts No additional

downloads necessary to receive style information

Disadvantage

This method can not control styles for multiple documents at once

Inline Styles

Advantages

Useful for small quantities of style definitions Can override other style specification

methods at the local level so only exceptions need to be listed in conjunction with other

style methods

Disadvantages

Does not distance style information from content (a main goal of SGML/HTML) Can not

control styles for multiple documents at once Author can not create or control classes of

elements to control multiple element types within the document Selector grouping

methods can not be used to create complex element addressing scenarios

XML

JOOMLA

CuteFTP

CMS

Functions

nI2br(string)

Anwser1:

nl2br() inserts a HTML tag <br> before all new line characters \n in a string.

echo nl2br("god bless \n you");

output:

god bless<br>

you

strstr(str,str);

string strstr ( string haystack, string needle ) returns part of haystack string from the first

occurrence of needle to the end of haystack. This function is case-sensitive.

strstr() returns part of a given string from the first occurrence of a given substring to the

end of the string. For example: strstr("user@example.com","@") will return

"@example.com".

stristr() is idential to strstr() except that it is case insensitive.

split

explode

preg_match(pattern,str)

We can use the preg_match() function with "/.*@(.*)$/" as

the regular expression pattern. For example:

preg_match("/.*@(.*)$/","http://info@abc.com",$data);

echo $data[1];

extract string "abc.com" from a string

"mailto:info@abc.com?subject=Feedback" using regular expression of PHP?

$text = "mailto:info@abc.com?subject=Feedback";

preg_match('|.*@([^?]*)|', $text, $output);

echo $output[1];

Note that the second index of $output, $output[1], gives the match, not the first one,

$output[0].

md5,crc32(),shat()

Crypto usage in PHP is simple, but that doesn’t mean it’s free. First off, depending on the

data that you’re encrypting, you might have reasons to store a 32-bit value in the database

instead of the 160-bit value to save on space. Second, the more secure the crypto is, the

longer is the computation time to deliver the hash value. A high volume site might be

significantly slowed down, if frequent md5() generation is required.

The major difference is the length of the hash generated. CRC32 is, evidently, 32 bits,

while sha1() returns a 128 bit value, and md5() returns a 160 bit value. This is important

when avoiding collisions.

eregi_replace() function is identical to ereg_replace() except that it ignores case

distinction when matching alphabetic characters.

func_num_args() function returns the number of parameters passed in.

__sleep returns the array of all the variables than need to be saved, while __wakeup

retrieves them.

On large strings that need to be formatted according to some length specifications, use

wordwrap() or chunk_split().

$formatted = ucwords("FYICENTER IS COLLECTION OF INTERVIEW

QUESTIONS");

print $formatted;

What will be printed is FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS.

ucwords() makes every first letter of every word capital, but it does not lower-case

anything else. To avoid this, and get a properly formatted string, it’s worth using

strtolower() first.

htmlspecialchars only takes care of <, >, single quote ‘, double quote " and ampersand.

htmlentities translates all occurrences of character sequences that have different meaning

in HTML.

htmlspecialchars() - Convert some special characters to HTML entities (Only the most

widely used)

htmlentities() - Convert ALL special characters to HTML entities

htmlentities() - Convert all applicable characters to HTML entities

This function is identical to htmlspecialchars() in all ways, except with htmlentities(), all

characters which have HTML character entity equivalents are translated into these

entities.

a) sizeof($array) - This function is an alias of count()

b) count($urarray) - This function returns the number of elements in an array.

Interestingly if you just pass a simple var instead of an array, count() will return 1.

Give the syntax of GRANT commands?

The generic syntax for GRANT is as following

GRANT [rights] on [database] TO [username@hostname] IDENTIFIED BY [password]

Now rights can be:

a) ALL privilages

b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE etc.

We can grant rights on all databse by usingh *.* or some specific database by database.*

or a specific table by database.table_name.

Give the syntax of REVOKE commands?

The generic syntax for revoke is as following

REVOKE [rights] on [database] FROM [username@hostname]

Now rights can be:

a) ALL privilages

b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE etc.

We can grant rights on all databse by usingh *.* or some specific database by database.*

or a specific table by database.table_name.

To know the image size use getimagesize() function

To know the image width use imagesx() function

To know the image height use imagesy() function

How can we increase the execution time of a php script?

By the use of void set_time_limit(int seconds)

Set the number of seconds a script is allowed to run. If this is reached, the script returns a

fatal error. The default limit is 30 seconds or, if it exists, the max_execution_time value

defined in the php.ini. If seconds is set to zero, no time limit is imposed.

When called, set_time_limit() restarts the timeout counter from zero. In other words, if

the timeout is the default 30 seconds, and 25 seconds into script execution a call such as

set_time_limit(20) is made, the script will run for a total of 45 seconds before timing out.

HOW CAN WE TAKE A BACKUP OF A MYSQL TABLE AND HOW CAN WE

RESTORE IT?

Answer 1:

Create a full backup of your database: shell> mysqldump tab=/path/to/some/dir opt

db_name

Or: shell> mysqlhotcopy db_name /path/to/some/dir

The full backup file is just a set of SQL statements, so restoring it is very easy:

shell> mysql "."Executed";

Answer 2:

To backup: BACKUP TABLE tbl_name TO /path/to/backup/directory

’ To restore: RESTORE TABLE tbl_name FROM /path/to/backup/directory

mysqldump: Dumping Table Structure and Data

Utility to dump a database or a collection of database for backup or for transferring the

data to another SQL server (not necessarily a MySQL server). The dump will contain

SQL statements to create the table and/or populate the table.

-t, no-create-info

Don't write table creation information (the CREATE TABLE statement).

-d, no-data

Don't write any row information for the table. This is very useful if you just want to get a

dump of the structure for a table!

WHAT TYPES OF IMAGES THAT PHP SUPPORTS?

Using imagetypes() function to find out what types of images are supported in your PHP

engine.

imagetypes() - Returns the image types supported.

This function returns a bit-field corresponding to the image formats supported by the

version of GD linked into PHP. The following bits are returned, IMG_GIF | IMG_JPG |

IMG_PNG | IMG_WBMP | IMG_XPM.

CHECK IF A VARIABLE IS AN INTEGER IN JAVASCRIPT

var myValue =9.8;

if(parseInt(myValue)== myValue)

alert('Integer');

else

alert('Not an integer');

Tools used for drawing ER diagrams.

Case Studio

Smart Draw

How can I know that a variable is a number or not using a JavaScript?

Answer 1:

bool is_numeric( mixed var)

Returns TRUE if var is a number or a numeric string, FALSE otherwise.

Answer 2:

Definition and Usage

The isNaN() function is used to check if a value is not a number.

Syntax

isNaN(number)

Parameter Description

number Required. The value to be tested

Friend functions

Sometimes a function is best shared among a number of different classes. Such functions can be

declared either as member functions of one class or as global functions. In either

case they can be set to be friends of other classes, by using a friend specifier in the class

that is admitting them. Such functions can use all attributes of the class which names

them as a friend, as if they were themselves members of that class.

A friend declaration is essentially a prototype for a member function, but instead of

requiring an implementation with the name of that class attached by the double colon

syntax, a global function or member function of another class provides the match.

class mylinkage

{

private:

mylinkage * prev;

mylinkage * next;

protected:

friend void set_prev(mylinkage* L, mylinkage* N);

void set_next(mylinkage* L);

public:

mylinkage * succ();

mylinkage * pred();

mylinkage();

};

void mylinkage::set_next(mylinkage* L) { next = L; }

void set_prev(mylinkage * L, mylinkage * N ) { N->prev = L; }

Friends in other classes

It is possible to specify a member function of another class as a friend as follows:

class C

{

friend int B::f1();

};

class B

{

int f1();

};

It is also possible to specify all the functions in another class as friends, by specifying the

entire class as a friend.

class A

{

friend class B;

};

Friend functions allow binary operators to be defined which combine private data in a

pair of objects. This is particularly powerful when using the operator overloading features

of C++. We will return to it when we look at overloading.

What are the advantages of stored procedures, triggers, indexes?

A stored procedure is a set of SQL commands that can be compiled and stored in the

server. Once this has been done, clients don't need to keep re-issuing the entire query but

can refer to the stored procedure. This provides better overall performance because the

query has to be parsed only once, and less information needs to be sent between the

server and the client. You can also raise the conceptual level by having libraries of

functions in the server. However, stored procedures of course do increase the load on the

database server system, as more of the work is done on the server side and less on the

client (application) side. Triggers will also be implemented. A trigger is effectively a type

of stored procedure, one that is invoked when a particular event occurs. For example, you

can install a stored procedure that is triggered each time a record is deleted from a

transaction table and that stored procedure automatically deletes the corresponding

customer from a customer table when all his transactions are deleted. Indexes are used to

find rows with specific column values quickly. Without an index, MySQL must begin

with the first row and then read through the entire table to find the relevant rows. The

larger the table, the more this costs. If the table has an index for the columns in question,

MySQL can quickly determine the position to seek to in the middle of the data file

without having to look at all the data. If a table has 1,000 rows, this is at least 100 times

faster than reading sequentially. If you need to access most of the rows, it is faster to read

sequentially, because this minimizes disk seeks.

How can increase the performance of MySQL select query?

We can use LIMIT to stop MySql for further search in table after we have received our

required no. of records, also we can use LEFT JOIN or RIGHT JOIN instead of full join

in cases we have related data in two or more tables.

How can we change the name of a column of a table?

MySQL query to rename table: RENAME TABLE tbl_name TO new_tbl_name

or,

ALTER TABLE tableName CHANGE OldName newName.

How can increase the performance of MySQL select query?

We can use LIMIT to stop MySql for further search in table after we have received our

required no. of records, also we can use LEFT JOIN or RIGHT JOIN instead of full join

in cases we have related data in two or more tables.

How can we change the name of a column of a table?

MySQL query to rename table: RENAME TABLE tbl_name TO new_tbl_name

or,

ALTER TABLE tableName CHANGE OldName newName.

When you want to show some part of a text displayed on an HTML page in red font

color? What different possibilities are there to do this? What are the

advantages/disadvantages of these methods?

There are 2 ways to show some part of a text in red:

1. Using HTML tag <font color="red">

2. Using HTML tag <span style="color: red">

When viewing an HTML page in a Browser, the Browser often keeps this page in its

cache. What can be possible advantages/disadvantages of page caching? How can

you prevent caching of a certain page (please give several alternate solutions)?

When you use the metatag in the header section at the beginning of an HTML Web page,

the Web page may still be cached in the Temporary Internet Files folder.

A page that Internet Explorer is browsing is not cached until half of the 64 KB buffer is

filled. Usually, metatags are inserted in the header section of an HTML document, which

appears at the beginning of the document. When the HTML code is parsed, it is read from

top to bottom. When the metatag is read, Internet Explorer looks for the existence of the

page in cache at that exact moment. If it is there, it is removed. To properly prevent the

Web page from appearing in the cache, place another header section at the end of the

HTML document. For example:

What are the different ways to login to a remote server? Explain the means,

advantages and disadvantages?

There is at least 3 ways to logon to a remote server:

Use ssh or telnet if you concern with security

You can also use rlogin to logon to a remote server.

Please give a regular expression (preferably Perl/PREG style), which can be used to

identify the URL from within a HTML link tag.

Try this: /href="([^"]*)"/i

How can I use the COM components in php?

The COM class provides a framework to integrate (D)COM components into your PHP scripts.

string COM::COM( string module_name [, string server_name [, int codepage]]) - COM

class constructor.

Parameters:

module_name: name or class-id of the requested component.

server_name: name of the DCOM server from which the component should be fetched. If

NULL, localhost is assumed. To allow DCOM com, allow_dcom has to be set to TRUE

in php.ini.

codepage - specifies the codepage that is used to convert php-strings to unicode-strings

and vice versa. Possible values are CP_ACP, CP_MACCP, CP_OEMCP, CP_SYMBOL,

CP_THREAD_ACP, CP_UTF7 and CP_UTF8.

Usage:

$word->Visible = 1; //open an empty document

$word->Documents->Add(); //do some weird stuff

$word->Selection->TypeText("This is a test…");

$word->Documents[1]->SaveAs("Useless test.doc"); //closing word

$word->Quit(); //free the object

$word->Release();

$word = null;

What changes I have to do in php.ini file for file uploading?

Make the following line uncomment like:

; Whether to allow HTTP file uploads.

file_uploads = On

; Temporary directory for HTTP uploaded files (will use system default if not

; specified).

upload_tmp_dir = C:\apache2triad\temp

; Maximum allowed size for uploaded files.

upload_max_filesize = 2M

How can I set a cron and how can I execute it in Unix, Linux, and windows?

Cron is very simply a Linux module that allows you to run commands at predetermined

times or intervals. In Windows, it's called Scheduled Tasks. The name Cron is in fact

derived from the same word from which we get the word chronology, which means order

of time.

The easiest way to use crontab is via the crontab command.

# crontab

This command 'edits' the crontab. Upon employing this command, you will be able to

enter the commands that you wish to run. My version of

Linux uses the text editor vi. You can find information on using vi here.

The syntax of this file is very important – if you get it wrong, your crontab will not

function properly. The syntax of the file should be as follows:

minutes hours day_of_month month day_of_week command

All the variables, with the exception of the command itself, are numerical constants. In

addition to an asterisk (*), which is a wildcard that allows any value, the ranges permitted

for each field are as follows:

Minutes: 0-59

Hours: 0-23

Day_of_month: 1-31

Month: 1-12

Weekday: 0-6

We can also include multiple values for each entry, simply by separating each value with

a comma.

command can be any shell command and, as we will see momentarily, can also be used to

execute a Web document such as a PHP file.

So, if we want to run a script every Tuesday morning at 8:15 AM, our mycronjob file will

contain the following content on a single line:

15 8 * * 2 /path/to/scriptname

This all seems simple enough, right? Not so fast! If you try to run a PHP script in this

manner, nothing will happen (barring very special configurations that have PHP compiled

as an executable, as opposed to an Apache module). The reason is that, in order for PHP

to be parsed, it needs to be passed through Apache. In other words, the page needs to be

called via a browser or other means of retrieving

Web content. For our purposes, I'll assume that your server configuration includes wget,

as is the case with most default configurations. To test your configuration, log in to shell.

If you're using an RPM-based system (e.g. Redhat or Mandrake), type the following:

# wget help

If you are greeted with a wget package identification, it is installed in your system.

You could execute the PHP by invoking wget on the URL to the page, like so:

# wget http://www.example.com/file.php

Now, let's go back to the mailstock.php file we created in the first part of this article. We

saved it in our document root, so it should be accessible via the Internet. Remember that

we wanted it to run at 4PM Eastern time, and send you your precious closing bell report?

Since I'm located in the Eastern timezone, we can go ahead and set up our crontab to use

4:00, but if you live elsewhere, you might have to compensate for the time difference

when setting this value.

This is what my crontab will look like:

0 4 * * 1,2,3,4,5 wget http://www.example.com/mailstock.php

Steps for the payment gateway processing?

An online payment gateway is the interface between your merchant account and your

Web site. The online payment gateway allows you to immediately verify credit card

transactions and authorize funds on a customer's credit card directly from your Web site.

It then passes the transaction off to your merchant bank for processing, commonly

referred to as transaction batching

What is the difference between Reply-to and Return-path in the headers of a mail

function?

Reply-to: Reply-to is where to delivery the reply of the mail.

Return-path: Return path is when there is a mail delivery failure occurs then where to

delivery the failure notification.

Explain about Type Juggling in php?

PHP does not require (or support) explicit type definition in variable declaration; a

variable's type is determined by the context in which that variable is used. That is to say,

if you assign a string value to variable $var, $var becomes a string. If you then assign an

integer value to $var, it becomes an integer.

An example of PHP's automatic type conversion is the addition operator '+'. If any of the

operands is a float, then all operands are evaluated as floats, and the result will be a float.

Otherwise, the operands will be interpreted as integers, and the result will also be an

integer. Note that this does NOT change the types of the operands themselves; the only

change is in how the operands are evaluated.

$foo += 2; // $foo is now an integer (2)

$foo = $foo + 1.3; // $foo is now a float (3.3)

$foo = 5 + "10 Little Piggies"; // $foo is integer (15)

$foo = 5 + "10 Small Pigs"; // $foo is integer (15)

If the last two examples above seem odd, see String conversion to numbers.

If you wish to change the type of a variable, see settype().

If you would like to test any of the examples in this section, you can use the var_dump()

function.

Note: The behavior of an automatic conversion to array is currently undefined.

Since PHP (for historical reasons) supports indexing into strings via offsets using the

same syntax as array indexing, the example above leads to a problem: should $a become

an array with its first element being "f", or should "f" become the first character of the

string $a? The current versions of PHP interpret the second assignment as a string offset

identification, so $a becomes "f", the result of this automatic conversion however should

be considered undefined. PHP 4 introduced the new curly bracket syntax to access

characters in string, use this syntax instead of the one presented above:

How can I embed a java programme in php file and what changes have to be done

in php.ini file?

There are two possible ways to bridge PHP and Java: you can either integrate PHP into a

Java Servlet environment, which is the more stable and efficient solution, or integrate

Java support into PHP. The former is provided by a SAPI module that interfaces with the

Servlet server, the latter by this Java extension.

The Java extension provides a simple and effective means for creating and invoking

methods on Java objects from PHP. The JVM is created using JNI, and everything runs

in-process.

Example Code:

getProperty('java.version') . ''; echo 'Java vendor=' . $system->getProperty('java.vendor') .

''; echo 'OS=' . $system->getProperty('os.name') . ' ' . $system->getProperty('os.version') .

' on ' . $system->getProperty('os.arch') . ' '; // java.util.Date example $formatter = new

Java('java.text.SimpleDateFormat', "EEEE, MMMM dd, yyyy 'at' h:mm:ss a zzzz"); echo

$formatter->format(new Java('java.util.Date')); ?>

The behaviour of these functions is affected by settings in php.ini.

Table 1. Java configuration options

Name

Default

Changeable

java.class.path

NULL

PHP_INI_ALL

Name Default Changeable

java.home

NULL

PHP_INI_ALL

java.library.path

NULL

PHP_INI_ALL

java.library

JAVALIB

PHP_INI_ALL

How To Read the Entire File into a Single String?

If you have a file, and you want to read the entire file into a single string, you can use the

file_get_contents() function. It opens the specified file, reads all characters in the file, and

returns them in a single string. Here is a PHP script example on how to

file_get_contents():

<?php

$file = file_get_contents("/windows/system32/drivers/etc/services");

print("Size of the file: ".strlen($file)."\n");

?>

This script will print:

Size of the file: 7116