The system catalog table pg_foreign_data_wrapper stores foreign-data wrapper definitions. A foreign-data wrapper is a mechanism by which you access external data residing on foreign servers.

    column type references description
    fdwname name Name of the foreign-data wrapper.
    fdwowner oid pg_authid.oid Owner of the foreign-data wrapper.
    fdwhandler oid pg_proc.oid A reference to a handler function that is responsible for supplying execution routines for the foreign-data wrapper. Zero if no handler is provided.
    fdwvalidator oid pg_proc.oid A reference to a validator function that is responsible for checking the validity of the options provided to the foreign-data wrapper. This function also checks the options for foreign servers and user mappings using the foreign-data wrapper. Zero if no validator is provided.
    fdwacl aclitem[] Access privileges; see GRANT and REVOKE for details.
    fdwoptions text[] Foreign-data wrapper-specific options, as “keyword=value” strings.

    Parent topic: System Catalogs Definitions