[GLLUG] BLOBs in Databases

[Clay Dowling]

Kami's usage matches my own. Filesystem management of data can be a little
involved, so a lot of people put that data in a blob. The other fields are
there to provide as lookup and indexing information.
On Feb 2, 2015 2:45 PM, "Kami Vaniea" <kami.vaniea at gmail.com> wrote:

> I occasionally use BLOBs in my work, though I tend to use MySQL over
> SQLite. For example, I once built a site that would do a kind of email
> based version repository. So you would email the system your doc file,
> and CC everybody who you wanted to view it. The system would then store
> the doc file, along with all future emailed doc files in one easily
> found place. Managing all that via the file system was annoying, and
> security problematic, so we threw the doc files into BLOBs. When the
> user wanted their file back the system would just read the contents of
> the BLOB back to them like it was a regular file.
>
> I've also done research projects where we automatically screen captured
> websites and needed to store the captures somewhere with a pile of
> metadata. So again, we used BLOBs. Other projects I've worked on needed
> to store binaries of various things. For example, web scraping projects
> that wanted to store the binaries of free apps so they could be analyzed
> in the future.
>
> I imagine BLOBs are also an excellent place to put things you don't want
> MySQL getting smart about. I've had way too many issues in the past with
> UTF8/16 text getting chewed up by either MySQL or whatever language I'm
> using. Putting data in a BLOB is a good way to flag "here be dragons" to
> the database so it doesn't try and index it or "improve" it in any way.
>
> I've never really tried reading the BLOB data directly from the DB.
> Normally I just use the DB the same way I would use the file system and
> code the application I'm writing to visualize whatever the binary is.
>
> - Kami
>
>
> On 02/02/2015 02:17 PM, Chick Tower wrote:
> > I've been doing a little research into SQLite, and they have a storage
> > class (they say it's slightly more general than a datatype) for binary
> > large objects (BLOB).  You can store photo images, or I suppose even
> > executables, in the database.  (I assume the same is true for other
> > databases.)  My question is why?  You can't view an image with SQLite.
> > How do you even get an image out of a database to view it?
> >
> >
> >
> > Perhaps I'm wrong in the intended use of the BLOB storage class.  It
> > says on the SQLite website "The value is a blob of data, stored exactly
> > as it was input."  So maybe it's intended for something other than
> > images, but, if so, what?  I still wonder how you extract a BLOB from a
> > database in order to do anything with it.  Does anyone know what to do
> > with BLOBs?
> >
> >
> >
>
>
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