Re: R: Re: R: R: Re: schema inspection

O rcolmegna@tiscali.it έγραψε στις Mar 17, 2006 :

> >
> >SELECT c1.relname,c2.relname from pg_constraint cons,pg_class c1, 
> pg_class
> >c2 where cons.conrelid=c1.oid and cons.confrelid = c2.oid;
> >
> >for column(s) names you will have to do extra homework.
> 
> Thanks!   I have obtained my query! Here is:
> 
> SELECT 
>   (SELECT relname FROM pg_catalog.pg_class WHERE oid=conrelid) AS 
> fromTbl,
>   (SELECT relname FROM pg_catalog.pg_class WHERE oid=confrelid) AS 
> toTbl,
>   (SELECT attname FROM pg_catalog.pg_attribute WHERE attrelid=conrelid 
> AND conkey[1]=attnum) AS viaCol
> FROM pg_catalog.pg_constraint AS rel WHERE contype='f';

Well thats it if you use only *single column* Foreign keys.
In the general case the above will need extra work.

Of course you will also have to ensure that the constraint is indeed
a FK constraint, that the column is not droped, etc....
which leads to the answer that enabling statement logging,
and then \d and watching the log is a very good friend too.

> 
> TIA
> Roberto Colmegna
> 
> 
> 
>         
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-- 
-Achilleus