MySQL Federated

MySQL Federated Storage Engine

The MySQL Federated storage engine for the MySQL relational database management system. It is a storage engine which allows a user to create a table that is a local representation of a foreign (remote) table. It utilises 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:

 create table t1 (
  a int,
  b varchar(32))
 ENGINE=FEDERATED CONNECTION='mysql://user@hostname/test/t1'

The connection URL is in the format of:

 scheme://user@host:port/schema/tablename

Upon creation of a Federated table, the user must ensure that the remote data source does indeed exist and an error will be issued.

External links

• MySQL Documentation on Federated Storage Engine

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