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List:       postgresql-sql
Subject:    Re: RES: [SQL] Joins between int and int[]
From:       Achilleus Mantzios <achill () matrix ! gatewaynet ! com>
Date:       2006-06-28 15:17:00
Message-ID: Pine.LNX.4.44.0606281813140.9179-100000 () matrix ! gatewaynet ! com
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O Rodrigo Sakai έγραψε στις Jun 28, 2006 :

> Thanks Mantzios, your answer helped a lot! But I have a lot of multi column
> foreign keys! Any other ideia??
> 

You must use/write a function that takes as an argument an array
and returns the elements of this array as a set.

I dont recall if some function like that exists in contrib
but you could search in the archives.

Also if my memory serves well there was a similar talk in th -sql list
some months ago.

Also keep in mind that if your queries are standardized then you
can write a program in C/perl/java/php/... that does what you want.
If your queries are ad-hoc then go the first approach.



>   Thanks in advance!
>  
> 
> -----Mensagem original-----
> De: Achilleus Mantzios [mailto:achill@matrix.gatewaynet.com] 
> Enviada em: quarta-feira, 28 de junho de 2006 04:01
> Para: Rodrigo Sakai
> Assunto: Re: [SQL] Joins between int and int[]
> 
> O Rodrigo Sakai έγραψε στις Jun 27, 2006 :
> 
> >   Hi,
> > 
> >  
> > 
> >   I want to use the system catalog tables/views to query some things, and
> > one of the queries I have to do is joining pg_attribute and pg_constraint
> to
> > know what constraint belongs to which table.attribute. My question is how
> > can I write the join clause between a int (pg_attribute.attnum) and int[ ]
> > (pg_constraint.conkey).
> 
> Are you having tables with multi column foreign keys?
> e.g. (a,b) REFERENCES partable(para,parb).
> 
> If not then join with pg_constraint.conkey[1],
> if yes then the problem becomes a little less trivial.
> 
> > 
> >  
> > 
> >  
> > 
> > The query is:
> > 
> >  
> > 
> > select relname, attname, attnotnull, atthasdef
> > 
> >   from pg_class as pc 
> > 
> >   inner join pg_attribute as pa
> > 
> >     on pc.oid=pa.attrelid
> > 
> >   inner join pg_constraint pcons
> > 
> >      on pc.oid=pcons.conrelid
> > 
> >     and pa.attnum = pcons.conkey                  -------> the problem
> > 
> >  
> > 
> >  
> > 
> >  Thanks!!! 
> > 
> >  
> > 
> > 
> 
> 

-- 
-Achilleus


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