[GLLUG] BLOBs in Databases

[Richard Houser]

Application Environments like Java Enterprise Edition explicitly forbid
accessing files directly from the filesystem.  Doing so usually just
creates a giant mess and applications that don't scale correctly.  It's one
of the banes JEE admins have to deal with with all the proprietary/broken
apps.  I'm sure other environments have similar constraints on bypassing
declared abstractions layers and hitting things directly.  By using
database nuetral SQL through a suitable layer (JDBC Datasource, etc.), you
can do things like take your SQLite application and spread it out into a
horizontal cluster of PostgreSQL backends, etc.  If you hit those resources
directly bypassing all the abstraction layers, you tend to make things
really, really difficult for any admins trying to work with your app.  Now,
that's not to say you can't create a resource wrapper of some sort that
internally just stores the content on filesystems, handles replication,
etc., but the point is that component can be independently swapped out,l
moved around, tec.

On Mon, Feb 2, 2015 at 2:17 PM, Chick Tower <c.e.tower at gmail.com> 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?
> --
>
>                                Chick
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