On 9/22/06, world_domination_kites <[EMAIL PROTECTED]> wrote:
> Carlo C8E Miron wrote:
> > Ciao world_domination_kites,
> > On 9/20/06, world_domination_kites <[EMAIL PROTECTED]> wrote:
> > > I recon what's required is a special cursor encapsulates all that CLOB
> > > foolishness such that calling code can pretend it's a big text field.
> > You can't do "LIKE" statements against a CLOB,
> > so you should also emulate the it as in:
> > http://www.developerdotstar.com/community/node/68
>
> Punto buon Carlo, I didn't think about that.
>
> try to execute the query
> except the error you get when you attempt a LIKE operation on a CLOB:
>    do a safer query -- same SELECT and FROM, WHERE 1<>1
>    inspect result attributes to determine CLOB columns
>    for each LIKE clause operating on a CLOB:
>         do simple regex stuff to replace them with CONTAINS clauses
>    try the query again
>    except the error you get when INTERMEDIA isn't working
>         for each LIKE clause operating on a CLOB:
>             do fancy regex stuff to replace with dbms_lob operations
>             execute the query

Scarying, but I can't think something simpler.

> I've never heard about a site where seen intermedia was working
> properly, so that step might not be worth it. But perhaps i've been
> unlucky...

Maybe is good enough to defer Oracle*text to the next release of
Oracle adapter ;)

> The "fancy regex stuff" step could be difficult for some strings. I'll
> have to have a look at dmbs_lob to see how helpfull it is. Transforming
> SQL dialect regex into a deterministic state machine using DMBS_LOB
> procedures might be to hard for my feeble brain. I suspect that's why
> INTERMEDIA was invented in the first place.

Strange. *I* was thinking that Oracle*text was invented to
deliberately cause DBA's headaches...

> Converting SQL dialect regex to python dialect (PCRE) would be easy,
> but pulling all the CLOBS out would absolutely suck performance wise
> (when many rows).

Yup, especially when the LIKE clause is the only (significant) filter...
Maybe is OK to accept some reasonable limitations, and point them out
in documentation?

> Pushing smarts back to Oracle sounds like
> re-implementing INTERMEDIA... fools errand.

Yeah.

> Is this problem likely to be the biggest barrier to getting the django
> Oracle backend working, or are there other known ice-burgs that I
> haven't discovered yet?

Isn't it big enough for you? *_*
Apart the 30-chars limit, of course...

Cheers,

-- 
Carlo C8E Miron, ICQ #26429731
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