MariaDB - Connection


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One way to establish a connection with MariaDB consists of using the mysql binary at the command prompt.

MYSQL Binary

Review an example given below.

[root@host]# mysql -u root -p

Enter password:******

The code given above connects to MariaDB and provides a command prompt for executing SQL commands. After entering the code, a welcome message should appear indicating a successful connection, with the version number displayed.

Welcome to the MariaDB monitor. Commands end with ; or \g. 
Your MariaDB connection id is 122323232 
Server version: 5.5.40-MariaDB-log
  
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.  
mysql> 

The example uses root access, but any user with privileges can of course access the MariaDB prompt and perform operations.

Disconnect from MariaDB through the exit command as follows −

mysql> exit

PHP Connection Script

Another way to connect to and disconnect from MariaDB consists of employing a PHP script. PHP provides the mysql_connect() function for opening a database connection. It uses five optional parameters, and returns a MariaDB link identifier after a successful connection, or a false on unsuccessful connection. It also provides the mysql_close() function for closing database connections, which uses a single parameter.

Syntax

Review the following PHP connection script syntax −

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

The description of the parameters is given below −

S.No Parameter & Description
1

server

This optional parameter specifies the host name running the database server. Its default value is “localhost:.3036.”

2

user

This optional parameter specifies the username accessing the database. Its default value is the owner of the server.

3

passwd

This optional parameter specifies the user's password. Its default value is blank.

4

new_link

This optional parameter specifies that on a second call to mysql_connect() with identical arguments, rather than a new connection, the identifier of the current connection will be returned.

5

client flags

This optional parameter uses a combination of the following constant values −

  • MYSQL_CLIENT_SSL − It uses ssl encryption.

  • MYSQL_CLIENT_COMPRESS − It uses compression protocol.

  • MYSQL_CLIENT_IGNORE_SPACE − It permits space after function names.

  • MYSQL_CLIENT_INTERACTIVE − It permits interactive timeout seconds of inactivity prior to closing the connection.

Review the PHP disconnection script syntax given below −

bool mysql_close ( resource $link_identifier );

If you omit the resource, the most recent opened resource will close. It returns a value of true on a successful close, or false.

Try the following example code to connect with a MariaDB server −

<html>
   <head>
      <title>Connect to MariaDB Server</title>
   </head>

   <body>
      <?php
         $dbhost = 'localhost:3036';
         $dbuser = 'guest1';
         $dbpass = 'guest1a';
         $conn = mysql_connect($dbhost, $dbuser, $dbpass);
      
         if(! $conn ) {
            die('Could not connect: ' . mysql_error());
         }
         
         echo 'Connected successfully';
         mysql_close($conn);
      ?>
   </body>
</html>

On successful connection, you will see the following output −

mysql> Connected successfully


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