Re: [PATCH] Support for Array ELEMENT Foreign Keys

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> This is a little sneaky, but I presume you only get the grammar
> conflict if you try to sneak the "each" or "element" or "each element"
> or whatever-you-call-it designator in BEFORE the column name. So what
> about just putting it afterwards? Something like this:

> FOREIGN KEY (a, b BY ELEMENT) REFERENCES ...

That's not the syntax we're having problems with, it's the column
constraint syntax; that is

CREATE TABLE t1 (c int[] REFERENCES t2);

It looks like we could support

CREATE TABLE t1 (c int[] REFERENCES BY ELEMENT t2);

but (1) this doesn't seem terribly intelligible to me, and
(2) I don't see how we modify that if we want to provide
at-least-one-match semantics later.

regards, tom lane