52.23. pg_foreign_data_wrapper
  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
   
  
| Name | Type | References | Description | 
|---|---|---|---|
| 
        oid
        | 
        oid
        | Row identifier (hidden attribute; must be explicitly selected) | |
| 
        fdwname
        | 
        name
        | Name of the foreign-data wrapper | |
| 
        fdwowner
        | 
        oid
        | 
        
          | Owner of the foreign-data wrapper | 
| 
        fdwhandler
        | 
        oid
        | 
        
          | 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 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[]
        | Access privileges; see GRANT and REVOKE for details | |
| 
        fdwoptions
        | 
        text[]
        | Foreign-data wrapper specific options, as " keyword=value " strings |