The Comment On Statement
The COMMENT ON statement allows you to add commentary to SQL programs. Using this statement, you can create a comment for the table as a whole and for individual columns in the table.
For example, to add a remark on the name column and on the status column of the employee table:
COMMENT ON COLUMN employee.name IS
'name in the format: lastname, firstname';
COMMENT ON COLUMN employee.status IS
'valid codes are:
01, exempt; 02, non-exempt; 03, temp';
To delete a comment, specify an empty string. For example, the comment on the status column can be deleted by the statement:
COMMENT ON COLUMN employee.status IS '';
For complete details, see the comment on statement in the SQL Reference Guide.