How do I check if PHP is connected to a database already?

Question

Basically in pseudo code I'm looking for something like

if (connected_to_any_database()) {     // do nothing } else {     mysql_connect(...) } 

How do I implement

connected_to_any_database() 

Answer 1

Have you tried mysql_ping()?

Update: From PHP 5.5 onwards, use mysqli_ping() instead.

Pings a server connection, or tries to reconnect if the connection has gone down.

if ($mysqli->ping()) {   printf ("Our connection is ok!\n");  } else {   printf ("Error: %s\n", $mysqli->error);  } 

Alternatively, a second (less reliable) approach would be:

$link = mysql_connect('localhost','username','password'); //(...) if($link == false){     //try to reconnect } 

Answer 2

Try using PHP's mysql_ping function:

echo @mysql_ping() ? 'true' : 'false'; 

You will need to prepend the "@" to suppose the MySQL Warnings you'll get for running this function without being connected to a database.

There are other ways as well, but it depends on the code that you're using.