ALTER USER MAPPING

Function

ALTER USER MAPPING changes the definition of a user mapping.

Precautions

If the password option is displayed, ensure that the usermapping.key.cipher and usermapping.key.rand files exist in the \$GAUSSHOME**/bin** directory of each node in openGauss. If the two files do not exist, use the gs_guc tool to generate them and use the gs_ssh tool to release them to the $GAUSSHOME**/bin** directory on each node.

Syntax

ALTER USER MAPPING FOR { user_name | USER | CURRENT_USER | PUBLIC }
    SERVER server_name
    OPTIONS ( [ ADD | SET | DROP ] option ['value'] [, ... ] )

In OPTIONS, ADD, SET, and DROP are operations to be performed. If these operations are not specified, ADD operations will be performed by default. option and value are the parameters and values of the corresponding operation.

Parameter Description

• user_name

  Specifies the username of the mapping.

  CURRENT_USER and USER match the name of the current user. PUBLIC is used to match all current and future user names in the system.

• server_name

  Specifies name of the server to which the user is mapped.

• OPTIONS

  Changes an option for the user mapping. The new option overwrites any previously specified option. ADD, SET, and DROP are operations to be performed. If the operation is not set explicitly, ADD is used. The option name must be unique and will be validated with the foreign data wrapper of the server.

  • Options supported by oracle_fdw are as follows:

    • user

      Oracle server username.

    • password

      Password of the Oracle user.

  • Options supported by mysql_fdw are as follows:

    • username

      Username of the MySQL server or MariaDB.

    • password

      User password of the MySQL server or MariaDB.

  • Options supported by postgres_fdw are as follows:

    • user

      Username of the remote openGauss database.

    • password

      User password of the remote openGauss database.

Helpful Links

CREATE USER MAPPING and DROP USER MAPPING

NOTE: In the Lite scenario, openGauss provides this syntax, but the USER MAPPING functions are unavailable.