COMMENT ON

COMMENT ON ... adds or updates the comment of an object.

Syntax

Details

COMMENT ON stores a comment about an object in the database. Each object can only have one comment associated with it, so successive calls of COMMENT ON to a single object will overwrite the previous comment.

To read the comment on an object you need to query the mz_internal.mz_comments catalog table.

Privileges

To comment on an object, the current role must be the owner of that object. Roles themselves do not have owners, so to comment on a role object you must have the CREATEROLE privilege. For more information on ownership and privileges, see Role-based access control.

Examples

--- Add comments.
COMMENT ON TABLE foo IS 'this table is important';
COMMENT ON COLUMN foo.x IS 'holds all of the important data';

--- Update a comment.
COMMENT ON TABLE foo IS 'holds non-important data';

--- Remove a comment.
COMMENT ON TABLE foo IS NULL;

--- Read comments.
SELECT * FROM mz_internal.mz_comments;