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
The privileges required to execute this statement are:
- Ownership of the object being commented on (unless the object is a role).
- To comment on a role, 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;