1 PHP Introduction to PHP Basic Syntax of PHP Variables, Constant, Data Type, Type Casting ...

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PHP

Introduction to PHP Basic Syntax of PHP

Variables, Constant, Data Type,Type Casting

Getting Data From Client PHP Database Manipulation

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Introduction PHP

PHP: Hypertext Preprocessor Originally called “Personal Home Page

Tools” Popular server-side scripting technology Open-source

Anyone may view, modify and redistribute source code

Supported freely by community Platform independent

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Basic Syntax of PHP

Basic application Scripting delimiters

<? php ?> Must enclose all script code

Variables preceded by $ symbol Case-sensitive

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Basic Syntax of PHP

End statements with semicolon Comments

// for single line /* */ for multiline

Filenames end with .php by convention

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1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"

2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

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4 

5 

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7 <?php

8 $name = "LunaTic"; // declaration

9 ?>

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11 <html xmlns = "http://www.w3.org/1999/xhtml">

12 <head>

13 <title>A simple PHP document</title>

14 </head>

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16 <body style = "font-size: 2em">

17 <p>

18 <strong>

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20 

21 Welcome to PHP, <?php print( "$name" ); ?>!

22 </strong>

23 </p>

24 </body>

25 </html>

Declare variable $name

Scripting delimiters

Single-line comment

Function print outputs the value of variable $name

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Basic Syntax of PHP

Simple PHP program

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Basic Syntax of PHP

Variable

Variable –area of memory set aside to store information, and it is assigned a particular identifier by the programmer.

Begin with a dollar ‘$’ sign. To assign a value to variable ,use the equals

sign or assignment ‘= ’ operator.

$author = “William Shakespear”;

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Basic Syntax of PHP

Case-sensitive :$author = “William

Shakespear”;

$Author = “William Shakespear”;

Above codes actually create two separate variables

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<html> <body> <? $actor=”Sean Connery”; echo $actor; ?> </body></html>

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Basic Syntax of PHP

Data Types

Data type Description int, integer Whole numbers (i.e., numbers without a decimal point). float, double Real numbers (i.e., numbers containing a decimal point). string Text enclosed in either single ('') or double ("") quotes. bool, Boolean True or false. array Group of elements of the same type. object Group of associated data and methods. Resource An external data source. NULL No value. Fig. 26.2 PHP data types.

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Basic Syntax of PHP

String Data Type

Holds textual information or words, and can even hold full sentences.

Everything stored inside quotation marks automatically becomes text, even numeric data.

$CarType= “Cadillac”;

$EngineSize=“2.6”;

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Basic Syntax of PHP

String Concatenation

The process of adding one string to another –example : Attach one string to the end of another.

Use .(period) as the concatenation operator.

$Car= $CarType.$EngineSize;

Cadillac2.6

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Basic Syntax of PHP

Numeric Data Type

Holds two different numeric data types- integers (whole numbers) & doubles (floating point numbers) .

No quotation marks.

$an_integer= 33;

$another_integer = -5797

$a_double= 4.567;

$another_double = -23.2

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Basic Syntax of PHP

Simple Mathematical Operations

Numerical operators can use to perform mathematical operations.

+ , * , - , / , % (8%5=3)

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<HTML>

<BODY>

<?php

$Salary = 15000;

$TaxRate = 20;

$Pension = 3;

$BeforePensionIncome = $Salary - (($Salary / 100) * $TaxRate);

$AfterPensionIncome = $BeforePensionIncome - (($BeforePensionIncome/100)*$Pension);

echo "Before Pension Deductions:$BeforePensionIncome<BR>";

echo "After Pension Deductions:$AfterPensionIncome";

?>

</BODY

</HTML>

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Basic Syntax of PHP

Type Casting

$NewVariable = 13;

$NewVariable = (string) $NewVariable ;

$NewVariable = 13;

$NewVariable = (string) $NewVariable ;

$NewVariable = (integer) $NewVariable ;

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Basic Syntax of PHPgettype and settype gettype()– to determine the current data type of

variable.gettype($number);

To display :$number = 5;

echo gettype($number);

Output :integer

settype()– to specifically set the data type.$number = 10;

settype($number, “string”);

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1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

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4 

5 

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7 <html xmlns = "http://www.w3.org/1999/xhtml">

8 <head>

9 <title>PHP data types</title>

10 </head>

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12 <body>

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14 <?php

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16 // declare a string, double and integer

17 $testString = "3.5 seconds";

18 $testDouble = 79.2;

19 $testInteger = 12;

20 ?>

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Assign a string to variable $testString

Assign a double to variable $testDouble

Assign an integer to variable $testInteger

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23 <?php print( $testString ); ?> is a string.<br />

24 <?php print( $testDouble ); ?> is a double.<br />

25 <?php print( $testInteger ); ?> is an integer.<br />

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27 <br />

28 Now, converting to other types:<br />

29 <?php

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31 // call function settype to convert variable

32 // testString to different data types

33 print( "$testString" );

34 settype( $testString, "double" );

35 print( " as a double is $testString <br />" );

36 print( "$testString" );

37 settype( $testString, "integer" );

38 print( " as an integer is $testString <br />" );

39 settype( $testString, "string" );

40 print( "Converting back to a string results in

41 $testString <br /><br />" );

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43 $data = "98.6 degrees";

Print each variable’s value

Call function settype to convert the data type of variable $testString to a double.

Call function settype to convert the data type of variable $testString to an integer.

Convert variable $testString back to a string

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44

45 // use type casting to cast variables to a

46 // different type

47 print( "Now using type casting instead: <br />

48 As a string - " . (string) $data .

49 "<br />As a double - " . (double) $data .

50 "<br />As an integer - " . (integer) $data );

51 ?>

52 </body>

53 </html>

Use type casting to cast variable $data to different types

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Type conversion

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Basic Syntax of PHP

Constants An identifier , which takes a value that cannot be

changed.

The Define Keyword Need a special keyword define. Don’t need to be prefixed with a dollar sign. Constant names are by convention all in upper case.

define(“FREEZINGPOINTCENTIGRADE”, 0);

Constant name Constant value

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Basic Syntax of PHP Constant that contains text – enclose the constant value

with quotation marks, example :define(“INDEPENDENCEDAY”, “31st August”);define(“COUNTRY”, “Malaysia”);

You can use echo() to display constants on web pages.

You can also append them to text, by using the concatenate operator.

echo “Independence Day is on” . INDEPENDENCEDAY ;

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Basic Syntax of PHP

Always make sure that constant name appears outside the quotation marks.

echo “Independence Day is on INDEPENDENCEDAY”;

OUTPUT = Independence Day is the INDEPENDENCEDAY

PHP also has its own built-in constants, example:echo PHP_OS;

(use to reflect values of OS that PHP is running on)

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Getting Data From Client

Notes can be obtained from:http://metalab.uniten.edu.my/~faridah/getting_data_from_client.doc

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PHP Database Manipulation

PHP supports for a wide range of databases.

The following databases are

currently supported:

Adabas DInterBase

PostgreSQL dBase FrontBase SQLite Empress mSQL Solid Direct MS-SQL

Sybase Hyperwave MySQL Velocis IBM DB2 ODBC Unix dbm Informix Oracle (OCI7 and OCI8) Ingres

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What is MySQL?

MySQL is a small database server MySQL is ideal for small and medium

applications MySQL supports standard SQL MySQL compiles on a number of

platforms MySQL is free to download and use

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Connecting to Database

<html><head><title>Connect Server</title></head><body><?$link = mysql_connect("localhost")or die("Connect Error: ".mysql_error());print "Successfully connected.\n";mysql_close($link);?></body></html>

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Inserting Data into Database

form_insert_record.php

<html><head><title>Birthdays Insert Form</title></head><body><table width="300" cellpadding="5" cellspacing="0" border="2"><tr align="center" valign="top"><td align="left" colspan="1" rowspan="1" bgcolor="64b1ff"><h3>Insert Record</h3><form method="POST" action="insert.php"><?print "Enter name: <input type=text name=name size=20><br>\n";

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Inserting Data into Database

print "Enter Birthday: <input type=text name=birthday size=10><br>\n";print "<br>\n";print "<input type=submit value=Submit><input type=reset>\n";?></form></td></tr></table></body></html>

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Inserting Data into Databaseinsert.php<?$name=$_POST['name']; $birthday=$_POST['birthday']; $db="mydatabase";$link = mysql_connect("localhost");if (! $link)die("Couldn't connect to MySQL");mysql_select_db($db , $link)or die("Couldn't open $db: ".mysql_error());//mysql_query ("INSERT INTO birthdays (name, //birthday) VALUES ('Peggy', 'June4')");mysql_query ("INSERT INTO birthdays (name, birthday) VALUES ('$name','$birthday')");echo "Record Inserted";mysql_close($link);?>

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Displaying Data from Databasedisplay.php<html><head><title>(Title Here)</title></head><body><?php$db="mydatabase";$link = mysql_connect("localhost");if (! $link)die("Couldn't connect to MySQL");mysql_select_db($db , $link)or die("Couldn't open $db: ".mysql_error());$result = mysql_query( "SELECT * FROM birthdays" )or die("SELECT Error: ".mysql_error());$num_rows = mysql_num_rows($result);

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Displaying Data from Databaseprint "There are $num_rows records.<P>";print "<table width=200 border=1>\n";while ($get_info = mysql_fetch_row($result)){ print "<tr>\n";foreach ($get_info as $field) print "\t<td><font face=arial size=1/>$field</font></td>\n"; print "</tr>\n";}print "</table>\n";mysql_close($link);?></body></html>

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Deleting Data from Databaseform_delete.php<html><head><title>Birthdays Delete Form</title></head><body><?$db="mydatabase";$link = mysql_connect("localhost");if (! $link)die("Couldn't connect to MySQL");mysql_select_db($db , $link)or die("Couldn't open $db: ".mysql_error());$result = mysql_query( "SELECT * FROM birthdays" )or die("SELECT Error: ".mysql_error());$num_rows = mysql_num_rows($result);

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Deleting Data from Databaseprint "There are $num_rows records.<P>";print "<table width=200 border=1>\n";while ($get_info = mysql_fetch_row($result)){ print "<tr>\n";foreach ($get_info as $field) print "\t<td><font face=arial size=1/>$field</font></td>\n"; print "</tr>\n"; }print "</table>\n";mysql_close($link);?><br>

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Deleting Data from Database<form method="POST" action="delete.php"><pre>Enter Line Number to Delete: <input type="text" name="id" size="5"><input type="submit" value="Submit"><input type="reset"></pre> </form></body></html>

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Deleting Data from Databasedelete.php<?$id=$_POST['id'];$db="mydatabase";$link = mysql_connect("localhost");if (! $link)die("Couldn't connect to MySQL");mysql_select_db($db , $link)or die("Couldn't open $db: ".mysql_error());mysql_query("DELETE FROM birthdays WHERE id=$id");echo "Record Updated";mysql_close($link);?>

Date post:	13-Dec-2015
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