Connecting PHP with MySQL

PHP provides mysql_connect() function to open a database connection. This function takes five parameters and returns a MySQL link identifier on success, or FALSE on failure.

Syntax:

mysql_connect(server, user, passwd, new_link, client_flag);

Parameter & Description:

Parameter	Description
server	Optional − The host name running database server. If not specified then default value is localhost:3306.
user	Optional − The host name running database server. If not specified then default value is localhost:3306.
passwd	Optional − The host name running database server. If not specified then default value is localhost:3306.
new_link	Optional − If a second call is made to `mysql_connect()` with the same arguments, no new connection will be established; instead, the identifier of the already opened connection will be returned.
client_flags	Optional − A combination of the following constants MYSQL_CLIENT_SSL − Use SSL encryption MYSQL_CLIENT_COMPRESS − Use compression protocol MYSQL_CLIENT_IGNORE_SPACE − Allow space after function names MYSQL_CLIENT_INTERACTIVE − Allow interactive timeout seconds of inactivity before closing the connection

NOTE: You can specify server, user, passwd in php.ini file instead of using them again and again in your every PHP scripts. Check php.ini file configuration.

Creating Database Connection

Using this function, we can establish a connection with MySQL database. Arguments are server name, user id and password.

<?php
	$servername = "localhost";
	$username = "root";
	$password = "";
	$conn = mysqli_connect($servername, $username, $password);
	if (!$conn)
		die("Connection failed: " . mysqli_connect_error());
		echo "Connected successfully";
?>

You can also connect with database without making the variable.

<?php
	$con=mysql_connect(localhost”,”root”,””);
	if($con)
		echo “connected”;
	else
		echo “Not connected”;
?>

Closing Database Connection

Its simplest function mysql_close() PHP provides to close a database connection. This function takes connection resource returned by mysql_connect() function. It returns TRUE on success or FALSE on failure.

Syntax:

bool mysql_close ( resource $link_identifier );

If a resource is not specified then last open and database is closed.

Example:

Try out following example to open and close a database connection.

<?php
	$dbhost = 'localhost:3036';
	$dbuser = 'guest';
	$dbpass = 'guest123';
	$conn = mysql_connect($dbhost, $dbuser, $dbpass);
	if(! $conn ) {
		die('Could not connect: ' . mysql_error());
	}
	echo 'Connected successfully';
	mysql_close($conn);
?>

Menu

Creating Database Connection

Closing Database Connection

Introduction to Algorithm

Recursion Algorithm