CODEWITHSUNDEEP
drupaldrupal-6
Behzad-Ravanbakhsh
Behzad-Ravanbakhsh

Reputation: 972

How to connect to multiple databases within Drupal

I want to deploy openpublish on about 5 drupal multisite by high traffic on website and want to use multiple database server but some tables should be shared. How to connect to multiple databases within Drupal by making share on 'users', 'sessions' and 'role' tables.

Upvotes: 0

Views: 4245

Answers (3)

Dharmendra Singh
Dharmendra Singh

Reputation: 1226

Sum times i wanted to retrieve data from other database in drupal then, i created a function in selected theme folder inside template.php file

    connect_to_database($un, $pass, $db, $insert)

it takes four parameters of the database username, password, databasename, and last is query

function connect_to_database($username,$password,$database,$query){
  $database_info = array(
      'host' => 'hosname',
      'database' => $database,
      'username' => $username,
      'password' => $password,
      'driver' => 'mysql'
  ); 
  Database::addConnectionInfo('coreapp', 'default', $database_info);
  db_set_active('newcon'); 
  $q = db_query($query);
  db_set_active('default');
  return $q; 
 }

Upvotes: 0

sillygwailo
sillygwailo

Reputation: 2007

The documentation on sharing tables says that you have to use a single database to share tables, but I've done it with multiple databases on the same server. I've done this by putting the database name before the prefix then adding a dot. So if your default database is called 'drupal', and your second database is called 'second_drupal', the prefixes would look like this in settings.php:

$db_prefix = array(
  "default" => "slave1_", // the prefix for tables that are not shared.
  "users" => "second_drupal.master_",
...

(Note that it doesn't matter what you call your default database, since it's the default database, you don't need to refer to it by name in the $db_prefix variable, as long as it's setup correctly in the settings.php file.)

http://thedrupalblog.com/setting-multi-site-drupal-6-installation-shared-databases-and-single-sign has some instructions, but I think that still assumes a single database server.

Upvotes: 1

ayush
ayush

Reputation: 14568

To allow multiple database connections, convert $db_url to an array.

<?php
$db_url['default'] = 'mysql://drupal:drupal@localhost/drupal';
$db_url['mydb'] = 'mysql://user:pwd@localhost/anotherdb';
$db_url['db3'] = 'mysql://user:pwd@localhost/yetanotherdb';
?>

To query a different database, simply set it as active by referencing the key name.

<?php
db_set_active('mydb');

db_query('SELECT * FROM table_in_anotherdb');

//Switch back to the default connection when finished.
db_set_active('default');
?>

But make sure all databases are of same kind.

Upvotes: 3

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