Re: Update and bytea problem...

Begin forwarded message:

> From: Jerry LeVan <jerry(dot)levan(at)eku(dot)edu>
> Date: December 9, 2005 10:45:35 PM EST
> To: Michael Fuhr <mike(at)fuhr(dot)org>
> Cc: Postgres General <pgsql-general(at)postgresql(dot)org>
> Subject: Re: [GENERAL] Update and bytea problem...
>
>
> On Dec 9, 2005, at 9:35 PM, Michael Fuhr wrote:
>
>> On Fri, Dec 09, 2005 at 08:46:17PM -0500, Jerry LeVan wrote:
>>> I am trying to write a general update command where
>>> there might be "bytea" fields involved.
>>>
>>> The update command is generated programatically.
>>>
>>> I am having some problems when a bytea field is
>>> involved.
>>
>> What language are you using and how are you escaping the bytea
>> data? Could you post a code snippet so we can see exactly what
>> you're doing?
>>
>> -- Michael Fuhr
>
> Sigh, it is really messy, I am writing in Tcl and using Pgtcl as
> the interface to Postgresql.
>
> This seems to work ok:
>
> insert into pics byteafield='<pg_escaped string>'
>
>
> I have been able to extract the byteafield and get the
> original file contents , jpg, png, etc...maybe I have been lucky?
>
> However
>
> update pics set byteafield='<pg_escaped string>' where
> byteafield='<other pg_escaped string>'
>
> has always failed for me unless the "other pg_escaped string" is a
> simple string.
> probably when pg_escaped string == string.
>
> Assuming I am not overlooking something obvious, I wonder how the
> "where clause" above is
> evaluated for bytea columns... do I need to unpgescape the string
> and then pg quote it?
>
> Something is not clear to me: I notice that pg_escaped strings can
> contain "'s are
> floating about in pg_escaped strings...
>
> Back to manuals...
>
> Jerry

Hmmm,

This seems to work...

update pic set byteafield='<pg_escaped string>' where byteafield
= pg_quote (<other pg_escaped string)

Still gotta do more testing. Tain't clear why I don't have to pg_quote
the <pg_escaped string> in the set clause...

Jerry