From: | Merlin Moncure <mmoncure(at)gmail(dot)com> |
---|---|
To: | erhaminus <erhaminus(at)o2(dot)pl> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Composite type, DEFAULT, NOT NULL, REFERENCES |
Date: | 2011-10-19 16:19:57 |
Message-ID: | CAHyXU0zqWmAwEz1Sh33j1OvTcQO_Uc5YaFT9CYwTxZA9AKyGQg@mail.gmail.com |
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Lists: | pgsql-general |
On Wed, Oct 19, 2011 at 9:32 AM, erhaminus <erhaminus(at)o2(dot)pl> wrote:
>
> Hi,
>
> Is a way to define DEFAULT, NOT NULL and REFERENCES for members of composite type?
>
> For example:
>
> -- type
> CREATE TYPE bibl.bibliography AS
> (
> edition TEXT,
> publisher_id BIGINT
> );
>
> -- table def
> create table bibl.monograph
> (
> id BIGSERIAL PRIMARY KEY NOT NULL,
> bibl bibl.bibliography
> );
>
> -- how to do that, assuming that:
> -- we want edition NOT NULL, DEFAULT with value "first"
> -- we want publisher_id reffering to bibl.publisher(id)
>
> This does not work for me:
>
> ALTER TABLE bibl.monograph ALTER COLUMN (bibl).is_bibliography SET NOT NULL;
> ALTER TABLE bibl.monograph ALTER COLUMN (bibl).is_bibliography SET DEFAULT false;
sure:
create table bibl.monograph
(
id BIGSERIAL PRIMARY KEY NOT NULL,
bibl bibl.bibliography check((bibl).is_bibliography is not
null) DEFAULT row(false, 'something');
);
create unique index on bibl.monograph(bibl);
create table a_table
(
bibl bibl.bibliography references bibl.monograph(bibl)
);
Not saying this is a good idea -- but it can be done. The only thing
you can't do is DOMAIN a composite type so you have to manually add
the check constraint to every table containing the type of you want to
enforce it.
merlin
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