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MySQLi – Connection

MySQL Connection Using MySQL Binary

You can establish the MySQL database using the mysql binary at the command prompt.

Example

Here is a simple example to connect to the MySQL server from the command prompt −

[root@host]# mysql -u root -p
Enter password:******

This will give you the mysqli command prompt where you will be able to execute any SQL command. Following is the result of above command −

The following code block shows the result of above code −

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2854760 to server version: 5.0.9

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

In the above example, we have used root as a user but you can use any other user as well. Any user will be able to perform all the SQL operations, which are allowed to that user.

You can disconnect from the MySQL database any time using the exit command at mysql> prompt.

mysql> exit
Bye

MySQL Connection Using PHP Script

PHP provides mysqli contruct or mysqli_connect() function to open a database connection. This function takes six parameters and returns a MySQL link identifier on success or FALSE on failure.

Syntax

$mysqli = new mysqli($host, $username, $passwd, $dbName, $port, $socket);
Sr.No.Parameter & Description
1$hostOptional − The host name running the database server. If not specified, then the default value will be localhost:3306.
2$usernameOptional − The username accessing the database. If not specified, then the default will be the name of the user that owns the server process.
3$passwdOptional − The password of the user accessing the database. If not specified, then the default will be an empty password.
4$dbNameOptional − database name on which query is to be performed.
5$portOptional − the port number to attempt to connect to the MySQL server..
6$socketOptional − socket or named pipe that should be used.

You can disconnect from the MySQL database anytime using another PHP function close().

Syntax

$mysqli→close();

Example

Try the following example to connect to a MySQL server −

Copy and paste the following example as mysql_example.php −

<html>
   <head>
      <title>Connecting MySQL Server</title>
   </head>
   <body>
      <?php
         $dbhost = 'localhost';
         $dbuser = 'root';
         $dbpass = 'root@123';
         $mysqli = new mysqli($dbhost, $dbuser, $dbpass);
         
         if($mysqli→connect_errno ) {
            printf("Connect failed: %s<br />", $mysqli→connect_error);
            exit();
         }
         printf('Connected successfully.<br />');
         $mysqli→close();
      ?>
   </body>
</html>

Output

Access the mysql_example.php deployed on apache web server and verify the output.

Connected successfully.

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