In this tutorial you will learn about the MySQL Connection and its application with practical example.
Before you perform any operations, you need to connect to MySQL server and select a MySQL database.
Table Of Contents−
Connecting to MySQL server and database using PHP
PHP uses mysql_connect() function to open a database connection.Here is prototype for mysql_connect() function.
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mysql_connect("$host", "$username", "$password"); |
| Parameter | Description |
|---|---|
| Host | The host name running database server. for using on local installation we use “localhost” as host name |
| username | The username accessing the database. for “localhost” dafualt username is “root“ |
| password | The password of the user accessing the database. If not specified then default is an empty password. |
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<?php $host="localhost"; $username="root"; $password=""; $db_name="emp_db"; $con=mysql_connect("$host", "$username", "$password")or die("cannot connect"); mysql_select_db("$db_name")or die("cannot select DB"); ?> |
MySQL persistent connection with PHP
MySQL persistent connection is a connection which first tries to find if any identical connection (i.e with same hostname, username and password) exists. If so, then commands followed will use that connection. If such a connection does not exist, it would create one. MySQL persistent connection can not be close using mysql_close(). Persistent connection is used for better performance out of your MySQL server
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<?php $host="localhost"; $username="root"; $password=""; $db_name="emp_db"; $con=mysql_pconnect("$host", "$username", "$password")or die("cannot connect"); mysql_select_db("$db_name")or die("cannot select DB"); ?> |
Disconnecting or closing a MySQL connection using PHP
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<?php mysql_close($con); ?> |
