COMMENT ON  -+-> DOMAIN domain-name ----+-> IS 'string' ;
              +-> COLUMN column-name ----+
              +-> TABLE table-name ------+
              +-> INDEX index-name ------+

Additional information available:

More Information

 The COMMENT ON statement adds or changes a comment about a domain,
 table, or column.  The comment is added to a table definition or
 replaces an existing comment in a table definition.  If you specify a
 column in the COMMENT ON statement, you must qualify the column name
 with a table name.

 You cannot create comments for view definitions.

 You cannot specify the COMMENT ON statement within a CREATE DATABASE
 statement.