之前有提及，Drupal支持比较常见的数据库种类，但其实不仅仅如此，在Drupal开发过程中，可能遇到跨数据库操作的情况，比如，从学生数据库中读取学生信息，Drupal还可以同时支持多数据库，Drupal多数据库操作如下：

1、配置Drupal多数据库，只需要配置settings.php 就可以实现

$databases = array(
‘default’ =>
array(
‘default’ =>
 array(
‘driver’ => ‘mysql’ ,
 ‘database’ => ‘databasename’ ,
 ‘username’ => ‘username’ ,
 ‘password’ => ‘password’ ,
 ‘host’ => ‘localhost’ ,
 ‘port’ => 3306,
 ‘prefix’ => ‘myprefix_’ ,
 ‘collation’ => ‘utf8_general_ci’ ,
),
),
‘legacy’ =>
array(
‘default’ =>
 array(
 ‘driver’ => ‘mysql’ ,
 ‘database’ => ‘legacydatabasename’ ,
  ‘username’ => ‘legacyusername’ ,
  ‘password’ => ‘legacypassword’ ,
  ‘host’ => ‘legacy’ ,
  ‘port’ => 6060,
  ‘prefix’ => ‘legacyprefix_’ ,
  ‘collation’ => ‘utf8_general_ci’ ,
  ),
  ),
);

2、在Drupal模块开发中，切换主\备数据库

//从其他数据库查询信息
db_set_active(‘legacy’ );
$result = db_query(“select * from table where uid = :uid” , array(‘:uid’ => $user->uid));
//切换到默认数据库
db_set_active(‘default’ )