middasgoldtouch wrote:

>
> As I understand how BLOBs work, the data goes into a different
> table and there is an address pointing to that table in the record.
> Would this mean it is possible to assign the same BLOB value to
> multiple records without adding the BLOB data every time?

As Helen's book will explain, Firebird BLOBS don't go in a different
table, but in what is effectively a different record. If they're
small, they go on the same data page with the main record. If
they're large, they go on a page by themselves. If they don't fit
on a single page, they start with an array of page numbers, then
get dumped onto those pages. If the array is larger than a page,
the blob is represented as an array of page numbers where each
page contains an array of blob data pages.

You can't share a blob between different records or records in
different tables - that would require bookkeeping so that the
shared blob doesn't go away before the last reference to it -
but blobs are shared between versions of a single record. If you
update a record with a blob but don't update the blob, you don't
get a second copy of the blob.


Good luck,

Ann