Re: Self referencing composite datatype
От | Chris Travers |
---|---|
Тема | Re: Self referencing composite datatype |
Дата | |
Msg-id | CAKt_ZfuLK9SVZ58gK9Wr9pm5-aZAyv7dxRiV3zwbkeKWj163Sg@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: Self referencing composite datatype (Alban Hertroys <haramrae@gmail.com>) |
Список | pgsql-general |
On Wed, Aug 7, 2013 at 11:38 PM, Alban Hertroys <haramrae@gmail.com> wrote:
On Aug 8, 2013, at 4:11, Sergey Konoplev <gray.ru@gmail.com> wrote:Or, instead of attempting to reference all child nodes from the parent, reference the parent node from each child node.
> create table node as (
> id integer primary key,
> r integer, s integer,
> children integer[] element references node
> );
>
> so you could download 9.3rc2 and experimant with it.
>
> Now (on <=9.2.x) you can create the table without FK
>
> create table node as (
> id integer primary key,
> r integer, s integer,
> children integer[]
> );
>
> and check integrity by triggers.
That's been supported in PG versions like forever and can be queried fairly efficiently using recursive CTE's since PG 9.
If you do this, have a position number, and use that for ordering. You need some sort of ordinality here.
Best Wishes,
Chris Travers
Alban Hertroys
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Best Wishes,
Chris Travers
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