| From: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Andrew Dunstan <andrew(at)dunslane(dot)net>, Marco Nenciarini <marco(dot)nenciarini(at)2ndquadrant(dot)it>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [PATCH] Support for Array ELEMENT Foreign Keys |
| Date: | 2012-10-19 20:55:50 |
| Message-ID: | CAGTBQpYyu_m6X+Diy8TEtgjMJp_m_PAxaZKa2wcyyXNBpWY0sQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, Oct 19, 2012 at 5:48 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> 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.
What about something more generic?
CREATE TABLE <tname> ( <cname> <type> [(<expr>)] REFERENCES <t2name>
[(<t2expr>)] )
Meaning, if <expr> is missing, it's taken <expr> = <cname>, if not,
it's the result of that expression the one that references the target
table.
Sounds crazy, but with ALL() and ANY() it ought to support lots of subcases.
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