> I really want to know ,if every field change triggers
> a re-write of the entire row including all blob info.

Blob fields are not reposted unless they have actually changed. You
will see the blob field in the update statement, but this is just
saving any existing blob-id within primary record as per normal.

Actual blob content is stored using a different process and so it can
be handled as an isolated situation without impacting the prepare of
the main record.

Geoff Worboys
Telesis Computing