Re: [HACKERS] Foreign keys: unexpected result from ALTER TABLE... ADD CONSTRAINT...

On Mon, 17 Jan 2000, Oliver Elphick wrote:

> I cannot do this pair of table creations directly, because they are mutually
> dependent.
>

I don't think this will ever work. I can't really decode your intentions
here but I recall that translating proper relational schemas (you know,
the ones with the bubbles and lines) into tables never creates this sort
of situation. Then again I could be wrong.

>
> create table purchased_job
> (
> supplier char(10) not null
> references supplier (id) match full,
> specification text,
> del_point char(2) not null
> references location (id) match full,
> import_licence bool default 'f',
> import_duty numeric(12,2),
> terms char(3),
> deliv_clear numeric(12,2),
>
> foreign key (product, supplier) references product_supplier (product,
> supplier) match full
> )
> inherits (job)
> ;
>
>
>
> create table product_supplier
> (
> product char(10) not null
> references purchased_job (product) match full,
> supplier char(10) not null
> references supplier (id) match full,
>
> primary key (product, supplier)
> )
> ;
>
> so I omitted the foreign key specification from the creation of purchased_job
> and tried to add it afterwards, but (after fixing a bug in gram.y) I found
> that ALTER TABLE ... ADD CONSTRAINT is not yet implemented. Is there, then, any
> way to create this mutual dependency?

Thanks for that fix, that was me changing the grammar for an ALTER TABLE /
ALTER COLUMN implementation, which now works btw.

--
Peter Eisentraut Sernanders vaeg 10:115
peter_e(at)gmx(dot)net 75262 Uppsala
http://yi.org/peter-e/ Sweden