The MySQL Federated storage engine for the MySQLrelational database management system is a storage engine which allows a user to create a table that is a local representation of a foreign (remote) table. It utilizes the MySQL client library API as a data transport, treating the remote data source the same way other storage engines treat local data sources whether they be MYD files (MyISAM), memory (Cluster, Heap), or tablespace (InnoDB). Each Federated table that is defined there is one .frm (data definition file containing information such as the URL of the data source). The actual data can exist on a local or remote MySQL instance.
To create a Federated table, one has to specify a URL in the "CONNECTION" string: