Re: Image Question

From: Tom Leylan (gee_at_iamtiredofspam.com)
Date: 02/15/04 

Date: Sat, 14 Feb 2004 20:46:00 -0500

"Trev Hunter" <hunter_trev@hotmail.com> wrote...
> Cheers, but some of the first words in my post were "IMHO" ;)

Clearly most replies are opinions but it is nice when people post the
rational behind. Situations are different and therefore perhaps the
conclusion.

> I admit, I was wrong to make so many assumptions about what the final
> product will be doing and how it will do it. I based my assumptions on an
> app that I recently wrote that stores documents of all types in a central
> database. I was wrong to assume that the OP's application was similar
> without more information. I did happen to notice your first post made the
> opposite assumption that there isn't any advantage to storing the images
in
> the database though...

It is great that you have experience with it. I was going to suggest to the
OP that he seek out people doing this type of thing (whatever it is he is
doing) so that he didn't just get responses based upon people taking 15
seconds out to reply. I'll admit that believe he will be at least "as well
off" by keeping the images outside but I intended to ask him what he thought
the advantages might be for storing them in the database. I can't think of
many... that doesn't mean that we can't post "it will be easier" but is that
in fact a "fact"?

Perhaps... how does he get 10,000 images into the database attached to the
proper records?

> 1) The Application will be used to store documents in a central location
> (this can apply to a web server, email application, windows application
> etc). This will involve users selecting a document from their local
machine
> and "uploading" it to the server.

I would have guessed from the short description that users wouldn't directly
upload files. So that's interesting.

> 2) When the user wants to view the file, they query the server. At this
> point, if there is no record in the database, the user can't get the file,
> so effectively there is no file anymore (even if there is a orphan file
> somewhere on the server that had its record deleted).

I don't think I get this. But anyway, I would guess that a user could
select only from records in the database. If it isn't in the database then
it doesn't qualify for downloading and/or viewing. It doesn't matter if the
an image is sitting in folder... I have images sitting in folders on my
webserver, you can't get them :-)

> 3) If a user deletes a file from the server, it is deleted from the
server,
> not the location that they originally uploaded it from.

Seems reasonable to me.

> To respond to your comments:
>
> > Synchronization for instance...
> > if you delete the record you have
> > effectively erased the image. Are we
> > certain destroying the image is the goal?
>
> See point (3) and again, sorry for the assumption.

We don't know that user routinely (if ever) keeps the images. Once
submitted they are "safely stored in the image archive" so what's the point?
Are the users working inhouse or subscribers to some service? I don't know
who owns the images.

> > If images are duplicated (the
> > "no image available" image for
> > instance) then you have stored
> > (possibly) hundreds of copies of that image.
>
> I would expect a bit of common sense on the part of the database schema
and
> application design to handle these situations. To handle no image
available,
> store Null and have a default image elsewhere. To handle multiple copies
of
> the same image, implement the schema with a join table and implement the
UI
> so that the user gets prompted if a similar image exists (based on other
> data about the image).

Seems reasonable.

> > Do you want to store
> > .jpeg, .gif and .png in
> > three separate columns?
>
> Again, a little bit of design intelligence would do here.

Perhaps but maybe I didn't explain it correctly. I can choose (from a
number of websites) to view movie trailers in one of three distinct formats
and often in low or high bandwidth versions. This means they have 6
different copies of the same film stored. If it is an image database such
that people can purchase and download the images it isn't hard to imagine
that a thumbnail would be required. Probably a larger image and possibly
another hi-definition version.

see: http://pro.corbis.com/

for information on image storage see:
http://sunsite.berkeley.edu/Imaging/Databases/

> > Would you suggest the same thing if the
> > guy was storing 20,000 video files?
>
> Probably not. They *did* state their requirements on this point in the
> original post though. The reason why I wouldn't recommend it is because of
> one of the con's mentioned in my first post (the part about maintaining a
> large single file for backups etc.) would far outweigh the benefits of
> storing in the database.

I agree. That's why I'm doubtful that storing the 10K images directly in
the database is a good idea. To be sure, it might be a great idea I just
(so far) don't think so.

> > To conclude something
> > with as little information as
> > has been posted isn't typically a good idea...
>
> Point taken and I'll be more careful in the future. I hope you can do the
> same before posting responses like your original one:

Sorry, I thought yours was the thoughtful response. Again I probably didn't
make myself clear on that. You gave "reasons" and so many times people just
post "opinions" never offering a basis for why they think what they think.

Which computer is best? <Blah Corp.> Oh that's great... why?

> > I can't see any particular
> > advantage to storing the
> > images in the database
> > can you? I can think of
> > a number of key reasons not to.

I see now... it was intended to be an invitation for discussion. Rather
than post "I think this... or that" I thought I might find out what the guy
with problem had thought about so far. He could be doing this for a large
corporation with a dedicated server and SQL Server or he could be putting
something together for the "dungeons and dragons" role-playing game he hosts
on a free internet site. I have no idea the kind of money or equipment (or
expertise) he has at his disposal.

> Thanks for the discussion. Hopefully I'll learn not to make assumptions
like
> this in the future.

It isn't you Trev... it is the way people post stuff in general. That's one
of the reasons "which computer language is best" type questions generate so
much heat and so little light. Few people ask "what do you want to do with
it" before mentioning the language they know.

Take care,
Tom

Relevant Pages

  • Re: How to store picture (*.jpg, *.bmp, *.gif) into sql database ?
    ... I'm for storing files on the file system. ... My perspective is from the simple .NET server and DB server ... If you store files in your database, the files must be streamed through ... Tampa .NET Koder wrote: ...
    (microsoft.public.dotnet.framework.aspnet)
  • Re: Image Question
    ... the database though... ... and "uploading" it to the server. ... > guy was storing 20,000 video files? ...
    (microsoft.public.dotnet.languages.vb)
  • Re: Upgrade to Server 2003
    ... That's an ADO message seen in VB6 for a variety of reasons. ... the database, but is not necessarily. ... > My client just upgraded their network from Novell to Server 2003. ...
    (microsoft.public.dotnet.general)
  • Re: Form quit, bypasses cancel in textboxes BeforUpdate
    ... Just about every pc database product. ... would love to find that shortcut, and the instant pain killer. ... >> have to resort to using the forms before update event). ... there is lots of reasons for the above: ...
    (microsoft.public.access.formscoding)
  • mysql as a file upload/download vector
    ... mysql server with the 'test' database still available can be used as a ... I mean storing the file data in a database. ... technology powered by the award-winning FoundScan engine. ...
    (Pen-Test)