Re: Foreign Key 'walker'?

On Nov 18, 2008, at 9:47 AM, Erwin Moller wrote:

> Hi group,
>
> Considering following (simplified) example:
>
> CREATE TABLE tblnr1(
> nr1id SERIAL PRIMARY KEY,
> firstname TEXT
> );
> CREATE TABLE tblnr2(
> nr2id SERIAL PRIMARY KEY,
> nr1id INTEGER REFERENCES tblnr1(nr1id)
> );
> CREATE TABLE tblnr3(
>  nr3id SERIAL PRIMARY KEY,
>  nr2id INTEGER REFERENCES tblnr2(nr2id)
> );
>
> Suppose I want to delete a record in tblnr1.
> Does Postgres has some command/procedure/function to list tables
> that have FK constraints on that table (tblnr1)
> and lists also the tables that have a FK constraint on tables that
> have a FK constraint on the first? etc.
> So I would like some kind of FK 'walker'.
>
> I want this because:
> 1) I hate DELETE CASCADE because I am chicken (So I use a script to
> delete all related records in the right order in a transaction)
> 2) I have a lot of tables and am afraid I miss some. And I am also a
> bit lazy .-)
>

Why not use something like this??

   CONSTRAINT fk_tname FOREIGN KEY (nr2id)
       REFERENCES tblnr2 MATCH SIMPLE ON UPDATE CASCADE ON DELETE NO
ACTION,

> Thanks for your time.
>
> Regards,
> Erwin Moller
>