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The Scenario

I have information spread out across a few databases and want to put all the information onto one webpage using PHP. I was wondering how I can connect to multiple databases on a single PHP webpage.

The Solution

You can make multiple calls to mysql_connect(), but if the parameters are the same you need to pass the value “true” as the forth parameter, otherwise the same connection is reused. Here is a demonstration on connecting multiple MySQL databases on a single Page.

Database One

    // Database ONE Connection

    // Constant variable declaration
    $host = 'localhost';
    $user = 'database_user';
    $pass = 'password';
    $name = 'database_name';

    // 1. Create database connection
    $db1_connection = mysql_connect($host, $user, $pass) or die(mysql_error());

    // 2. Select database to use
    $db1 = mysql_select_db($qn_name, $db1_connection) or die(mysql_error());

Database Two

    // Database TWO Connection

    // 1. Create the second database connection
    // Passing the "true" value in the forth parameter here
    $db2_connection = mysql_connect($host, $user, $pass, true) or die(mysql_error());

    // 2. Select database to use
    $db2 = mysql_select_db($name, $db2_connection) or die(mysql_error());

Problem solved! Happy coding…

4 Responses so far.

1. WP Themes says:

   30 June, 2010 at 11:56 PM

   Nice post and this fill someone in on helped me alot in my college assignement. Say thank you you as your information.
2. Monie says:

   31 July, 2010 at 10:13 PM

   Not sure if this is the best way of doing it. Share with me if you have a different method?
3. dean says:

   21 August, 2011 at 11:18 AM

   Can you explain more on the true value? why do you need that? why can’t you just the same syntax (with increment) again?
4. Monie says:

   21 August, 2011 at 1:11 PM

   From the PHP MYSQL reference, the syntax is as follows:

   mysql_connect(server,user,pwd,newlink,clientflag)

   The “newlink” refer to as:

   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

   Link: http://www.w3schools.com/PHP/func_mysql_connect.asp