Re: Storing images in PostgreSQL databases (again)

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От Leonel Nunez
Тема Re: Storing images in PostgreSQL databases (again)
Дата
Msg-id 33317.201.155.188.137.1160099765.squirrel@enelserver.com
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Ответ на Re: Storing images in PostgreSQL databases (again)  (Bill Moran <wmoran@collaborativefusion.com>)
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> "Leonel Nunez" <lnunez@enelserver.com> wrote:
>>
>> > If the database had built-in functions to manipulate images (make a
>> > thumbnail, add text ont it.., make a montage of two pictures) and I
>> could
>> > write something like
>> > select thumbnail(image_field, 100, 100) from images_table
>> > that would be a good reason to go the db route versus the filesystem
>> > route.
>
> <snip>
>
>> With Python   and  the  python imaging library   you can do  this  :
>>
>> image is a bytea  field
>>
>> curs = conn.cursor ()
>> curs.execute( "select image from images where name = %s" ,(thename, ))
>> row = curs.fetchone()
>> if row:
>>    im = Image.open (StringIO.StringIO(row[0]))
>>    im.thumbnail (160,120 )
>>    imagetmp = StringIO.StringIO()
>>    im.save ( imagetmp  , "JPEG")
>>    print ("Content-type: image/jpeg\n\n")
>>    print ( imagetmp.getvalue())
>
> I think part of the point, which you missed, is the convenience of having
> the thumbnailing as part of the SQL language by making it a stored
> procedure.
>
> I did a presentation for WPLUG not too long ago where I created C
> functions in Postgres compiled against the GSOAP library that allowed
> you to make simple SOAP calls in SQL within PostgreSQL.  Neat stuff.
>
> The problem with creating those kinds of functions is the CPU overhead.
> We'll be generating the thumbnails and storing them in a "thumbnail"
> field in the record, so we don't have to regenerate the thumbnail each
> time it's needed.
>
> BTW: our reason for keeping the thumbnails in fields is so they can be
> replicated with Slony along with the rest of the database.
>
> --
> Bill Moran
>
> We meddle.  People don't like to be meddled with.  We tell them what to
> do,
> what to think.  Don't run, don't walk.  We're in their homes and in their
> heads and we haven't the right.
>
>         River Tam
>
>



you are 100%  right

Leonel


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