[Zope] Can Zope extract an image (BLOB) from an RDB ?

Doug Hellmann hellmann@GNNcast.net
Mon, 07 Feb 2000 15:20:15 +0000


Chas,

We extract LOBs from Oracle successfully every day, although not from
DTML.  We're using ZOracleDA 2.1.0 with DCOracle version 1.2.1 (I
think).  I'd recommend grabbing the latest version of ZOracleDA if you
are starting out fresh.  Look at the docs/docstrings/README for DCOracle
(not ZOracleDA) for a description of how LOB access works.  In short, I
just added the LOB column to my query and got a big string with the data
in it as a return value.  There is another mode of operation in which
you get an object from which you have to read data before you can use
it.

I would hazard to say that serving images directly from Oracle is going
to be fairly slow.  Depending on the performance you require and the
load you expect, you might do better using an approach such as we
outlined in our presentation at IPC8
(http://www.zope.org/Members/reedwade/IPC8/) of using Zope as a
read-through cache for Oracle.  This has worked very well for us for our
needs.

Good luck,
Doug

-- 
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Doug Hellmann                  Healtheon / WebMD
Software Engineer              http://www.webmd.com