ALTER USER MAPPING FOR { user_name | USER | CURRENT_USER | PUBLIC } SERVER server_name OPTIONS ( [ ADD | SET | DROP ] option ['value'] [, ... ] )
Note: The following description applies only to Postgres-XC
USER MAPPING has not been supported by Postgres-XC yet. This command may be supported in the future releases.
ALTER USER MAPPING conforms to ISO/IEC 9075-9 (SQL/MED). There is a subtle syntax issue: The standard omits the FOR key word. Since both CREATE USER MAPPING and DROP USER MAPPING use FOR in analogous positions, and IBM DB2 (being the other major SQL/MED implementation) also requires it for ALTER USER MAPPING, PostgreSQL diverges from the standard here in the interest of consistency and interoperability.