Re: dynamic crosstab

From: Pierre Chevalier <pierre(dot)chevalier1967(at)free(dot)fr>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: dynamic crosstab
Date: 2010-01-29 00:15:53
Message-ID: 4B6228B9.1050504@free.fr
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Pavel Stehule claviota:
>> Nut... Idea! (careful...) what about if we do, just like in a VIEW, a CREATE
>> OR REPLACE, systematically when we do this kind of function? The only
>> drawback I can think of is that we can't have anything dependant on the VIEW
>> we generate.
>>
> no, you cannot do it. You cannot create view and same statements ask
> on this view on top level.
>
> if you would to understand it - you have to understand to process
> pipeline: parser, planner, optimizer, executor. If you understand to
> this stages, then you will understand what is possible and what not.
>

Ok, ok. I just imagine, for now... I guess I have to swallow a big bunch
of doc and code before I can really understand this, so I take your word.

>> Another idea (more danger...): what about setting a sort of flag which says
>> that this VIEW should *not* be included in the planner? And it will have
>> unexpected number of columns? Would this be *absolutely* impossible to
>> state?
>>
> :) sorry - you can do it, but not in pg - or you have to rewrite 50%
> of low level code
>

Oh well, not tonight... ;)

>>> look on SPI interface
>>> http://www.postgresql.org/docs/8.4/interactive/spi.html
>>> http://www.postgresql.org/docs/8.4/interactive/spi-examples.html
>>> but you have to use cursor based interface.
>>>
>> I'll try to Read The French Manual, rather than the one in English! I'll
>> look for it...
>>
>> But the whole point is: this need of a generic cross-tab is really annoying
>> for a large number of people, it has been there for a long time, and I know
>> some people who just walk away from postgreSQL only because this feature is
>> lacking, and they return happily to their m$-access, therefore ignoring the
>> pure wealth of postgreSQL: sad, isn't it?...
>>
> ms access hasn't klient-server architecture. Generating of crosstab is
> client side task - more - iOLTP databases are not the best tool for
> it. Better are OLAP databases with GUI clients - like Excel or MS
> Access.
>

OK, I got your point. Thanks for explaining patiently!
In fact, what I wanted to do within postgresql, I'd better try to do it
somewhere else, with a client more in an OLAP style.

I got so used to do *everything* inside postgresql (well, through psql),
complex queries, nested things, with visual graphs generated by
queries... that I thought it was just endless! Oh well, this is the limit.

Now, talking about GUI clients: I've been looking for a long time for a
decent tool that could replace an access, to interact with my postgresql
database. So far, the best I found is knoda, for my needs. I battled a
bit with oobase, not very convincing, or I missed something. Apparently,
as I can google, quite a few projects have been abandoned. Does someone
knwo if there something new, on this side?

I'm also quite "nostalgique" (English?) of dBase IV, and its screens,
forms and tables with the F4 key... I was wandering whether a project of
an ncurses-based front-end for postgreql (actually, it could be for any
FLOSS database, I guess) could be developed: again, does someone know if
such a project exists?

--
Pierre Chevalier Mesté Duran 32100 Condom
Tél : 09 75 27 45 62 - 06 37 80 33 64
http://pierremariechevalier.free.fr/
Logiciels Libres dans le Gers: http://gnusquetaires.org/

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