# Zend_Application_Resource_Multidb

`Zend_Application_Resource_Multidb` is used to initialize multiple Database connections. You can use the same options as you can with the Db Resource Plugin. However, for specifying a default connection, you can also use the 'default' directive.

## Setting up multiple Db Connections

Below is an example INI configuration that can be used to initialize two Db Connections.

    [production]
    resources.multidb.db1.adapter = "pdo_mysql"
    resources.multidb.db1.host = "localhost"
    resources.multidb.db1.username = "webuser"
    resources.multidb.db1.password = "XXXX"
    resources.multidb.db1.dbname = "db1"

    resources.multidb.db2.adapter = "pdo_pgsql"
    resources.multidb.db2.host = "example.com"
    resources.multidb.db2.username = "dba"
    resources.multidb.db2.password = "notthatpublic"
    resources.multidb.db2.dbname = "db2"
    resources.multidb.db2.default = true

## Retrieving a specific database adapter

When using this resource plugin you usually will want to retrieve a specific database. This can be done by using the resource's `getDb()`. The method `getDb()` returns an instance of a class that extends `Zend_Db_Adapter_Abstract`. If you have not set a default database, an exception will be thrown when this method is called without specifying a parameter.

    $resource = $bootstrap->getPluginResource('multidb');
    $db1 = $resource->getDb('db1');
    $db2 = $resource->getDb('db2');
    $defaultDb = $resource->getDb();

## Retrieving the default database adapter

Additionally, you can retrieve the default database adapter by using the method `getDefaultDb()`. If you have not set a default adapter, the first configured db adapter will be returned. Unless you specify `FALSE` as first parameter, then `NULL` will be returned when no default database adapter was set.

Below is an example that assumes the Multidb resource plugin has been configured with the INI sample above:

    $resource = $bootstrap->getPluginResource('multidb');
    $db2 = $resource->getDefaultDb();

    // Same config, but now without a default db:
    $db1 = $resource->getDefaultDb();
    $null = $resource->getDefaultDb(false); // null