Non-trivial rewriting sql query - Mailing list pgsql-hackers

From Oleg Bartunov
Subject Non-trivial rewriting sql query
Date
Msg-id Pine.LNX.4.33.0106271154370.10127-100000@zen.sai.msu.ru
Whole thread Raw
Responses Re: Non-trivial rewriting sql query  (Alex Pilosov <alex@pilosoft.com>)
Re: Non-trivial rewriting sql query  (Jan Wieck <JanWieck@Yahoo.com>)
List pgsql-hackers
Jan,

we're thinking about possibility to integrate our full-text search
into postgres. There are several problems we should thinking about
but for now we have a question about rewrite system.

Is't possible to rewrite SQL query and execute it. Currently we build
sql query outside of postgres using perl.

Let's consider some simple example:

create table tst ( a int4, b int4, c int4);
   select * from tst where a=2 and c=0;

we need something like:
   select * from tst where str and c=0;

where str is a string resulting by call ourfunc(table.a, 2)
and looks like  'b=2*2 or b=(2-1)'

i.e. instead of original select we need to execute rewritten select
   select * from tst where (b=2*2 or b=(2-1)) and c=0;

in other words we need to know is't possible to recognise
(operator, field,table) and rewrite part of sql by
result of calling of ourfunc().

We're not sure if it's a question of rewrite system though.

Any pointers where to go would be very nice.
Regards,
    Oleg



pgsql-hackers by date:

Previous
From: Hannu Krosing
Date:
Subject: Re: Re: 7.2 items
Next
From: Zeugswetter Andreas SB
Date:
Subject: AW: functions returning records