Mysql multiple database connection doesn't work

Question

I just tried to connect a secondary database like this example bellow but i don't know why refuse to work. Any idea?

I mention that each database connection works properly individualy.

$db_HOST = "localhost";
$db_USER = "db_user";
$db_PASS = "db_pass";
$db_NAME1 = "db_test1";
$db_NAME2= "db_test2";

$db_LINK1 = mysql_connect($db_HOST, $db_USER, $db_PASS) or die("Technical revision. Please try again later!");
mysql_select_db($db_NAME1, $db_LINK1) or die("Couldn't select database");

$db_LINK2 = mysql_connect($db_HOST, $db_USER, $db_PASS, true) or die("Technical revision. Please try again later!");
mysql_select_db($db_NAME2, $db_LINK2) or die("Couldn't select database");

Errors i get in the log file:

PHP Warning:  mysql_fetch_array() expects parameter 1 to be resource, boolean given in /config/global/variables.php on line 27

PHP Warning:  mysql_fetch_array() expects parameter 1 to be resource, boolean given in config/global/hello.php on line 3

Thank you!

Use PDO, mysql_connect is deprecated. https://stackoverflow.com/questions/12859942/why-shouldnt-i-use-mysql-functions-in-php — Blackbam, Jun 27 '17 at 16:02
@AlexHowansky none of those die errors log. Simply a blank page. — Adrian, Jun 27 '17 at 16:04
Possible duplicate of [mysql\_connect() fails with empty warning](https://stackoverflow.com/questions/8658977/mysql-connect-fails-with-empty-warning) — Blackbam, Jun 27 '17 at 16:05
Sure: http://php.net/manual/en/pdo.connections.php. You can connect two ten different databases if you want and each of the connection has its own access variable then. — Blackbam, Jun 27 '17 at 16:07
@Rushikumar sory, i found 2 errors, i just updated in the question section. — Adrian, Jun 27 '17 at 16:11

score 0 · Answer 1 · answered Jun 27 '17 at 16:11

You should really use PDO but your code works if you use your link in your db select. For example:

$db1 = mysql_connect($hostname, $username, $password); 
$db2 = mysql_connect($hostname, $username, $password, true); 

mysql_select_db('database1', $db1);
mysql_select_db('database2', $db2);

that should work. You forgot to select which database should be used on every link.

score 0 · Accepted Answer · answered Jun 27 '17 at 16:16

Do the following (with PDO instead of mysql_connect as the latter is deprecated):

$db_HOST = "localhost";
$db_USER = "db_user";
$db_PASS = "db_pass";
$db_NAME1 = "db_test1";
$db_NAME2= "db_test2";

try {
    $db_LINK1 = new PDO('mysql:host='.$db_HOST.';dbname='.$db_NAME1, $db_USER, $db_PASS);
    foreach($db_LINK1->query('SELECT * from FOO') as $row) {
        print_r($row);
    }
    $dbh = null;
} catch (PDOException $e) {
    print "Error!: " . $e->getMessage() . "<br/>";
    die();
}

try {
    $db_LINK2 = new PDO('mysql:host='.$db_HOST.';dbname='.$db_NAME2, $db_USER, $db_PASS);
    foreach($db_LINK2->query('SELECT * from FOO') as $row) {
        print_r($row);
    }
    $dbh = null;
} catch (PDOException $e) {
    print "Error!: " . $e->getMessage() . "<br/>";
    die();
}

More info here: php.net/manual/en/pdo.connections.php

If the second connection fails check the exact error message.

Hi. I just tried to implement your code but i don't now what exactly means FOO in this case. Can be users SQL table or something? — Adrian, Jul 07 '17 at 12:58

Adrian · Answer 3 · 2017-06-27T16:34:15.877

0

I thnk I found the problem. I forgot to change all queries accordind to the new multiple connection. LE: Solve confirmed! Thank you all!

edited Jun 27 '17 at 16:34

answered Jun 27 '17 at 16:23

Adrian

159
7

Still you should use pdo ... ^^ – Blackbam Jun 27 '17 at 16:27
1

@Blackbam yes, you're right. I will try to implement your PDO code example. Thank you so much for your time :) – Adrian Jun 27 '17 at 16:32

Mysql multiple database connection doesn't work

3 Answers3