CREATE FOREIGN DATA WRAPPER(7)                            SQL Commands                            CREATE FOREIGN DATA WRAPPER(7)



NAME
       CREATE FOREIGN DATA WRAPPER - define a new foreign-data wrapper


SYNOPSIS
       CREATE FOREIGN DATA WRAPPER name
           [ VALIDATOR valfunction | NO VALIDATOR ]
           [ OPTIONS ( option 'value' [, ... ] ) ]


DESCRIPTION
       CREATE  FOREIGN  DATA WRAPPER creates a new foreign-data wrapper. The user who defines a foreign-data wrapper becomes its
       owner.

       The foreign-data wrapper name must be unique within the database.

       Only superusers can create foreign-data wrappers.

PARAMETERS
       name   The name of the foreign-data wrapper to be created.

       VALIDATOR valfunction
              valfunction is the name of a previously registered function that will be called to check the generic options given
              to the foreign-data wrapper, as well as to foreign servers and user mappings using the foreign-data wrapper. If no
              validator function or NO VALIDATOR is specified, then options will not be checked at creation time.  (Foreign-data
              wrappers  will  possibly  ignore or reject invalid option specifications at run time, depending on the implementa-
              tion.) The validator function must take two arguments: one of type text[], which will contain the array of options
              as  stored in the system catalogs, and one of type oid, which will be the OID of the system catalog containing the
              options. The return type is ignored; the function should indicate invalid options using the ereport() function.

       OPTIONS ( option 'value' [, ... ] )
              This clause specifies options for the new foreign-data wrapper.  The allowed option names and values are  specific
              to  each  foreign  data  wrapper  and  are  validated using the foreign-data wrapper library. Option names must be
              unique.

NOTES
       At the moment, the foreign-data wrapper functionality is very rudimentary. The purpose of foreign-data wrappers,  foreign
       servers,  and user mappings is to store this information in a standard way so that it can be queried by interested appli-
       cations.  One such application is dblink; see in the documentation. The functionality to  actually  query  external  data
       through a foreign-data wrapper library does not exist yet.

       There  is currently one foreign-data wrapper validator function provided: postgresql_fdw_validator, which accepts options
       corresponding to libpq connection parameters.

EXAMPLES
       Create a foreign-data wrapper dummy:

       CREATE FOREIGN DATA WRAPPER dummy;


       Create a foreign-data wrapper postgresql with validator function postgresql_fdw_validator:

       CREATE FOREIGN DATA WRAPPER postgresql VALIDATOR postgresql_fdw_validator;


       Create a foreign-data wrapper mywrapper with some options:

       CREATE FOREIGN DATA WRAPPER mywrapper
           OPTIONS (debug 'true');


COMPATIBILITY
       CREATE FOREIGN DATA WRAPPER conforms to ISO/IEC 9075-9 (SQL/MED), with the exception that  the  VALIDATOR  clause  is  an
       extension and the clauses LIBRARY and LANGUAGE are not yet implemented in PostgreSQL.

       Note, however, that the SQL/MED functionality as a whole is not yet conforming.

SEE ALSO
       ALTER  FOREIGN  DATA  WRAPPER  [alter_foreign_data_wrapper(7)], DROP FOREIGN DATA WRAPPER [drop_foreign_data_wrapper(7)],
       CREATE SERVER [create_server(7)], CREATE USER MAPPING [create_user_mapping(7)]



SQL - Language Statements                                  2011-09-22                             CREATE FOREIGN DATA WRAPPER(7)