CREATE_FOREIGN_DATA_WRAPPER(7) - Man pages

CREATE FOREIGN DATA WRAPPPostgreSQL 15.7 DocumenCREATE FOREIGN DATA WRAPPER(7)

NAME
       CREATE_FOREIGN_DATA_WRAPPER - define a new foreign-data wrapper

SYNOPSIS
       CREATE FOREIGN DATA WRAPPER name
           [ HANDLER handler_function | NO HANDLER ]
           [ VALIDATOR validator_function | 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.

       HANDLER handler_function
           handler_function is the name of a previously registered function
           that will be called to retrieve the execution functions for foreign
           tables. The handler function must take no arguments, and its return
           type must be fdw_handler.

           It is possible to create a foreign-data wrapper with no handler
           function, but foreign tables using such a wrapper can only be
           declared, not accessed.

       VALIDATOR validator_function
           validator_function 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 options for foreign servers, user
           mappings and foreign tables 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 implementation.) 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 report
           invalid options using the ereport(ERROR) 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's
           validator function. Option names must be unique.

NOTES
       PostgreSQL's foreign-data functionality is still under active
       development. Optimization of queries is primitive (and mostly left to
       the wrapper, too). Thus, there is considerable room for future
       performance improvements.

EXAMPLES
       Create a useless foreign-data wrapper dummy:

           CREATE FOREIGN DATA WRAPPER dummy;

       Create a foreign-data wrapper file with handler function
       file_fdw_handler:

           CREATE FOREIGN DATA WRAPPER file HANDLER file_fdw_handler;

       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 HANDLER and VALIDATOR clauses are extensions and
       the standard clauses LIBRARY and LANGUAGE are not 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)),
       CREATE FOREIGN TABLE (CREATE_FOREIGN_TABLE(7))

PostgreSQL 15.7                      2024       CREATE FOREIGN DATA WRAPPER(7)

Generated by dwww version 1.15 on Sat Jun 29 02:07:34 CEST 2024.