Robert,

> Firebird 2.1 introduced the COMMENT statement for setting metadata
> description. How do I add a multi line comment to an object using

COMMENT

> (without altering the system tables directly)?

Curious... why multi-line?

If you update the system tables directly you accomplish your goal:

UPDATE RDB$RELATIONS SET
RDB$DESCRIPTION = :MyComment
WHERE
UPPER( RDB$RELATION_Name) = 'MYTABLE'


Sean