extracting blobs (jpg) directly to the web woth perl DBI ??

From: "Dr(dot) Hans-Christian Waldmann" <waldmann(at)samson(dot)fire(dot)uni-bremen(dot)de>
To: pgsql-interfaces(at)postgresql(dot)org
Subject: extracting blobs (jpg) directly to the web woth perl DBI ??
Date: 2001-02-09 15:20:43
Message-ID: 200102091520.f19FKh920316@samson.fire.uni-bremen.de
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Dear List,

I have a table with several string columns (defining product properties)
and one blob-column of type "oid" (actually showing the product in jpg-
Format). Currently I am using postgresql 7.0.2 along with perl 5.6 and
the perl DBI 1.14 in order to query the table from a cgi-form. The
jpg is first exported to the filesystem, with a url pointing to it
in the html-response (query-results from non-oid columns). This works
fine assuming a rather low query rate. But you have to give unique names
to the jpg-files, (f)lock them, delete them, and concurrent hits
for the same picture are hard to handle, etc. What I would like to learn
about is a way to read contents of a blob-column (known type: jpg)
_directly_ out to the webserver (apache) and into the response page.
Is it possible ? Or am I asking something absurd ? If it is not possible,
could someone point me to a secure method of assuring result integrity when
reading out the same picture to the fs upon multiple queries (referencing the
same picture)? There must be a method since there quite a lot of online
catalogues around. To be true I am a statistics/math programmer with very
little experience in the web domain. Please let me know if have any ideas.

Thank you

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PD Dr. Hans C Waldmann
Methodology & Applied Statistics in Psychology & the Health Sciences

ZFRF / University of Bremen / Grazer Str 6 / 28359 Bremen / Germany
waldmann(at)samson(dot)fire(dot)uni-bremen(dot)de / http://samson.fire.uni-bremen.de

friend of: AIX PERL POSTGRES ADABAS SAS SPSS TEX
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