Post on 14-Mar-2020
transcript
PHP Development - Introduction
Php Hypertext Processor
• PHP stands for PHP: Hypertext Preprocessor
• PHP is a server-side scripting language, like ASP
• PHP scripts are executed on the server
• PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.)
• PHP is an open source software
Php Hypertext Processor
Php Hypertext Processor
Php Hypertext Processor
Php Hypertext Processor
Taken from Udemy.com
Php Hypertext Processor
Taken from Udemy.com
Php Hypertext Processor
• PHP files can contain text, HTML tags and scripts
• PHP files are returned to the browser as plain HTML
• PHP files have a file extension of ".php“ (most common), ".php3", or ".phtml"
• Php script starts with <?php
• Ends with ?>
• Php script can be placed anywhere in document
• File ends in .php
• Each instruction must end with a semicolon ;
• Semicolon acts as a separator between instructions
Php Scripts
<html> <head> </head> <body> <?php echo "Hello World!"; ?> </body> </html>
Hello World
<html> <head> </head> <body> Hello World! </body> </html>
Hello World
• Comments help make code more readable/understandable
• Beneficial for third party to understand code
• Ignored by compiler
• Use // to create a single line comment
• Use /* ….. */ to create a multiple line comment
Comments
<html> <body> <?php //This is a comment /* This is a comment block */ ?> </body> </html>
Comments
Outputting Strings
• The echo() function outputs one or more strings
• The print() function can also be used
• echo() is faster than print() <?php
echo "This text spans multiple lines."; ?>
This text spans multiple lines.
Outputting Strings
<?php $str = "What’s my name?"; echo $str; echo "<br />"; echo $str."<br />I don't know!"; ?>
What’s my name? What’s my name? I don't know!
PHP Development – MySQL
Dr. Mark Hughes
Why Databases
Some examples of PHP and MySQL being used together are:
• Banner Rotation. On this site, where each banner is, a PHP script is called. This opens a database and picks a random banner from it to show the visitor.
• Forums. Hundreds of forums (message boards) on the internet are run using PHP and MySQL.
• Databases. One quite obvious example is sites which get all there information from a database. Websites. If you have a large website and you want to change the design it can take a very long time to update and upload all the pages. With PHP and MySQL your whole website could be just one or two PHP scripts.
Creating Databases
Creating Databases
• Retrieve all users from Shenyang
• Retrieve all users from Dublin who are under 30
• Retrieve all users who have a username that begins with j
• Retrieve all users that have a yahoo email address
• Print out users under 30 by order of their age
Phpmyadmin Access Denied Issue
• Go to C:\wamp\apps\phpmyadmin3.5.1
• Open file called config.inc.php
• Change lines $cfg['Servers'][$i]['user'] = ''; $cfg['Servers'][$i]['password'] = ‘’ To username and password of mysql installed on local machine
Connecting to Databases
Before you can access data in a database, you must create a connection to the database. In PHP, this is done with the mysql_connect() function. Syntax mysql_connect(servername,username,password);
Connecting to Databases
Parameter Description
servername Optional. Specifies the server to connect to. Default value is "localhost:3306"
username Optional. Specifies the username to log in with. Default value is the name of the user that owns the server process
password Optional. Specifies the password to log in with. Default is ""
Connecting to Databases
<?php $con = mysql_connect("localhost",“username",“password"); if (!$con) { die('Could not connect: ' . mysql_error()); } // some code ?>
Closing a connection
<?php $con = mysql_connect("localhost",“username",“password"); if (!$con) { die('Could not connect: ' . mysql_error()); } // some code mysql_close($con); ?>
Database Connection
<?php $db_hostname = ‘localhost’; $db_database = ‘mydatabase’; $db_username = ‘’username’ $db_password = ‘password’; ?>
<?php require_once ‘login.php’; $database = mysql_connect($db_hostname, $db_username, $db_password); ….. …… ?>
Creating Databases
• The CREATE DATABASE statement is used to create a database in MySQL.
Syntax CREATE DATABASE database_name Can be executed in three ways: • Phpmyadmin • MySQL command line • Php Code
• <?php $con = mysql_connect("localhost",“username",“password"); if (!$con) { die('Could not connect: ' . mysql_error()); } if (mysql_query("CREATE DATABASE my_db",$con)) { echo "Database created"; } else { echo "Error creating database: " . mysql_error(); } mysql_close($con); ?>
Creating Databases
Creating Databases
The CREATE TABLE statement is used to create a table in MySQL. Syntax CREATE TABLE table_name ( column_name1 data_type, column_name2 data_type, column_name3 data_type, .... )
Creating Databases <?php $con = mysql_connect("localhost",“username",“password"); if (!$con) { die('Could not connect: ' . mysql_error()); } // Create database if (mysql_query("CREATE DATABASE my_db",$con)) { echo "Database created"; } else { echo "Error creating database: " . mysql_error(); } // Create table mysql_select_db("my_db", $con); $sql = "CREATE TABLE Persons ( FirstName varchar(15), LastName varchar(15), Age int )"; // Execute query mysql_query($sql,$con); mysql_close($con); ?>
Creating Databases
• The INSERT INTO statement is used to add new records to a database table.
Syntax It is possible to write the INSERT INTO statement in two forms. • The first form doesn't specify the column names where the data
will be inserted, only their values: INSERT INTO table_name VALUES (value1, value2, value3,...) • The second form specifies both the column names and the values
to be inserted: INSERT INTO table_name (column1, column2, column3,...) VALUES (value1, value2, value3,...)
Inserting into Databases
<?php $con = mysql_connect("localhost",“username",“password"); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("my_db", $con); mysql_query("INSERT INTO Users (FirstName, LastName, email) VALUES (‘James', ‘Murphy',’james.murphy@yahoo.com’)"); mysql_close($con); ?>
Database Querying
$query="SELECT * FROM contacts"; $result=mysql_query($query); • In this case the whole contents of the database
is now contained in a special array with the name $result.
• Before you can output this data you must change each piece into a separate variable. There are two stages to this.
Database Querying
<?php // Make a MySQL Connection mysql_connect("localhost", "admin", "1admin") or die(mysql_error()); mysql_select_db("test") or die(mysql_error()); // Retrieve all the data from the "example" table $result = mysql_query("SELECT * FROM example") or die(mysql_error()); // store the record of the "example" table into $row $row = mysql_fetch_array( $result ); // Print out the contents of the entry echo "Name: ".$row['name']; echo " Age: ".$row['age']; ?>
Database Querying
'$row = mysql_fetch_array( $result );‘ • mysql_fetch_array returns the first row in a MySQL Resource
in the form of an associative array.
• $result is now a MySQL Resource containing data from your MySQL table, "example". Data is being stored in $result, but it is not yet visible to visitors of your website.
• When we pass $result into the mysql_fetch_array function -- mysql_fetch_array($result) -- an associative array (name, age) is returned.
Database Querying
'$row = mysql_fetch_array( $result );‘ • In a MySQL table "example," there are two fields :
name and age. These names are the keys to extracting the data from our associative array. To get the name we use $row['name'] and to get the age we use $row['age'].
• PHP is case sensitive when you reference MySQL column names, so be sure to use capitalization in your PHP code that matches the MySQL column names!
Database Querying
<?php // Make a MySQL Connection $query = "SELECT * FROM example"; $result = mysql_query($query) or die(mysql_error()); while($row = mysql_fetch_array($result)){ echo $row['name']. " - ". $row['age']; echo "<br />"; } ?>
Database Querying
<?php // Make a MySQL Connection $query = "SELECT * FROM example"; $result = mysql_query($query) or die(mysql_error()); $no_of_rows = mysql_num_rows($result); For(int $i = 0; $i < $no_of_rows; $i++) { $row = mysql_fetch_array($result); // process rows here } ?>
MySQLi
MySQL Extensions
$db = new mysqli('localhost', 'user', 'pass', 'demo'); if($db->connect_errno > 0) { die('Unable to connect to database [' . $db->connect_error . ']'); }
• Object Oriented Extensions to MySQL functionality
• Recommended approach to use
• Original procedural approach no longer being maintained
MySQL Extensions
$query = "SELECT * FROM `users` WHERE `status`='bonkers'"; $result = $db->query($query)
if($result->num_rows > 0) { while($row = $result->fetch_assoc()) { echo stripslashes($row['username']); } } else { echo 'NO RESULTS'; } // CLOSE CONNECTION $db->c
MySQL Extensions (Create Table)
<?php // connect to the MySQL server $conn = new mysqli('localhost', 'root', 'pass', 'tests'); // check connection if (mysqli_connect_errno()) { exit('Connect failed: '. mysqli_connect_error()); } // sql query for CREATE TABLE $sql = "CREATE TABLE `users` ( `id` INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY, `name` VARCHAR(25) NOT NULL, `pass` VARCHAR(18) NOT NULL, `email` VARCHAR(45), `reg_date` TIMESTAMP ) CHARACTER SET utf8 COLLATE utf8_general_ci"; // Performs the $sql query on the server to create the table if ($conn->query($sql) === TRUE) { echo 'Table "users" successfully created'; } else { echo 'Error: '. $conn->error; } $conn->close(); ?>
MySQL Extensions (Insert Statement)
<?php // connect to the "tests" database $conn = new mysqli('localhost', 'root', 'pass', 'tests'); // check connection if (mysqli_connect_errno()) { exit('Connect failed: '. mysqli_connect_error()); } // sql query for INSERT INTO users $sql = "INSERT INTO `users` (`name`, `pass`, `email`) VALUES ('Marius', 'faith', 'name@domain.net')"; // Performs the $sql query on the server to insert the values If ($conn->query($sql) === TRUE) { echo 'users entry saved successfully'; } else { echo 'Error: '. $conn->error; } $conn->close(); ?>
MySQL Extensions