Check Mysql Connection Existence in PHP

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5

I had this question recently, how to check if there is an open connection with mysql? Everyone knows that to use the mysql_real_escape_string need to have a connection right, so I wanted to check if there is one, if yes ai use mysql_real_escape_string.

php mysql connection
  • 2

    A little strange question, because, by your code you can know if you have connection or not, a thing also and a tip stop using mysql_connect, this code is deprecated in the new versions of your PHP, so use PDO (http://us1.php.net/manual/en/class.pdo.php) or Mysqli (http://us1.php.net/manual/en/class.mysqli.php) At this link you can get the error simply by mysql_error (http://us1.php.net/manual/en/function.mysql-error.php), the first example can help you !!!

  • 2

    pq not using mysql functions_*

3 answers

7

You can check like this:

<?php
if(is_resource($connection) && get_resource_type($connection) === 'mysql link')
{
    //esta conectado.
}
else
{
    //não está conectado
}
?>

or simply this one that returns false if there is no connection:

mysql_thread_id($connection)

Source: SO AS.

7

The function mysql_ping returns FALSE if there is no connection, with the advantage of trying to reconnect before, if the connection has been lost in a script:

mysql_ping ([ $identificador_da_conexao ] )

See the manual:

http://br1.php.net/manual/en/function.mysql-ping.php

Important: the functions of mysql_ do not exist from PHP 5.5. Learn how to use the functions mysqli_, which are safer and complete. Click here and see the documentation.

  • 2

    Here comes the question: First of all, you are opening the connection in your code?

  • 3

    And there’s another interesting thing: This answer is technically correct for what was asked, but the question and the answer are already as obsolete as the functions in question.

  • Just scoring the PHP version. In version 5.5 it became obsolete but still worked. It was removed in version 7.0.0. In its documentation it says: "This extension is obsolete since PHP 5.5.0 and has been removed in PHP 7.0.0." : link

  • @Christianoribeirosoares is a valid observation, but I hope you have noticed that the question and comments are from 2014 :D - however, I need to pass on some old answers to update. - grateful for the reminder

2

Thank you Jorge B.! The solution that works best is:

<?php


if(is_resource($connection) && get_resource_type($connection) === 'mysql link'){

//esta conectado.

} else {

//não está conectado

}


?>

Why using the mysql_ping() or the mysql_thread_id(), when the connection is closed, these commands return error because there is no Resource for them to work...

  • Mark Jorge’s answer as the correct one, so it signals to other users. Do not repeat the answer.

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