PG_FOREIGN_DATA_WRAPPER

PG_FOREIGN_DATA_WRAPPER records foreign-data wrapper definitions. A foreign-data wrapper is the mechanism by which external data, residing on foreign servers, is accessed.

**Table 1** PG_FOREIGN_DATA_WRAPPER columns
Name	Type	Reference	Description
oid	oid	-	Row identifier (hidden attribute, which must be specified)
fdwname	name	-	Name of a foreign-data wrapper
fdwowner	oid	OID in PG_AUTHID	Owner of a foreign-data wrapper
fdwhandler	oid	OID in PG_PROC	References a handler function that is responsible for supplying execution routines for a foreign-data wrapper The value is 0 if no handler is provided.
fdwvalidator	oid	OID in PG_PROC	References a validator function that is responsible for checking the validity of the options given to a foreign-data wrapper, as well as options for foreign servers and user mappings using the foreign-data wrapper. The value is 0 if no validator is provided.
fdwacl	aclitem[]	-	Access permissions
fdwoptions	text[]	-	Foreign-data wrapper specific option, expressed in a string in the format of keyword=value