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
| Column Type Description | 
|---|
| 
        Row identifier | 
| 
        Name of the foreign-data wrapper | 
| 
        Owner of the foreign-data wrapper | 
| 
        References a handler function that is responsible for supplying execution routines for the foreign-data wrapper. Zero if no handler is provided | 
| 
        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 | 
| 
        Access privileges; see Section 5.7 for details | 
| 
        Foreign-data wrapper specific options, as “keyword=value” strings |