## 52.23. `pg_foreign_data_wrapper`

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 The catalog `pg_foreign_data_wrapper` stores foreign-data wrapper definitions. A foreign-data wrapper is the mechanism by which external data, residing on foreign servers, is accessed.

**Table 52.23. `pg_foreign_data_wrapper` Columns**

|                                                                                                                                                      Column Type<br/><br/> Description                                                                                                                                                      |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                                                    `oid` `oid`<br/><br/> Row identifier                                                                                                                                                     |
|                                                                                                                                         `fdwname` `name`<br/><br/> Name of the foreign-data wrapper                                                                                                                                         |
|                                                                                                            `fdwowner` `oid` (references [`pg_authid`](catalog-pg-authid.html).`oid`)<br/><br/> Owner of the foreign-data wrapper                                                                                                            |
|                                                      `fdwhandler` `oid` (references [`pg_proc`](catalog-pg-proc.html).`oid`)<br/><br/> References a handler function that is responsible for supplying execution routines for the foreign-data wrapper. Zero if no handler is provided                                                      |
|`fdwvalidator` `oid` (references [`pg_proc`](catalog-pg-proc.html).`oid`)<br/><br/> References a validator function that is responsible for checking the validity of the options given to the foreign-data wrapper, as well as options for foreign servers and user mappings using the foreign-data wrapper. Zero if no validator is provided|
|                                                                                                                       `fdwacl` `aclitem[]`<br/><br/> Access privileges; see [Section 5.7](ddl-priv.html) for details                                                                                                                        |
|                                                                                                                      `fdwoptions` `text[]`<br/><br/> Foreign-data wrapper specific options, as “keyword=value” strings                                                                                                                      |

