> -----Original Message-----
> From: Ann W. Harrison [mailto:aharrison@...]
> Sent: Wednesday, 16 June 2004 6:38 AM
> To: firebird-support@yahoogroups.com; firebird-support@yahoogroups.com
> Subject: Re: [firebird-support] Maximum BLOB size and BLOB reuse ?
>
> At 03:49 PM 6/15/2004, benedicte_asselin wrote:
>
>
> >- what is the maximum content size of a BLOB
>
> That depends on the page size, but it is approximately
> (page_size - 20) ^^3
>
> > can we use some 'seek'
> >inside a BLOB? I saw something like that in the .h but not in the
> >documentation
>
> That requires creating a stream blob which hasn't been documented
> in years. I don't know if it works.
>
> >- can I reuse a BLOB? i.e., insert several raws putting same
> >ISC_QUAD (==BLOB ID) in a given column ?
>
> No. Part of storing a blob is changing it from temporary to
> permanent. Once a blob has been stored, the temporary id no
> longer exists.

I have a similar requirement in my application where some blobs are common
to multiple rows. The way I thought I, would approach this is simply have a
(sub)-table which only has two columns; auto-generated id & blob & use the
id as a foreign key in the main table instead of storing multiple copies of
the same blob. If there is much redundancy & many rows, I believe this would
be efficient, certainly in reduced db size, if blobs are jpg images or other
large blobs structures. Even if the blobs are simply "memo" type text blobs,
this technique would eliminate requirement to update multiple rows in the
main table if the "memo" text is edited on a regular basis!

Regards

Ken Galbraith
Hospitality Software Design

> Regards,
>
> Ann
>