| From: | Patrick Francelle <patrick(at)francelle(dot)name> |
|---|---|
| To: | Pantelis Theodosiou <ypercube(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
| Cc: | Lætitia Avrot <laetitia(dot)avrot(at)gmail(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, bpd0018(at)gmail(dot)com, vik(dot)fearing(at)2ndquadrant(dot)com, coelho(at)cri(dot)ensmp(dot)fr, pgsql-hackers(at)lists(dot)postgresql(dot)org |
| Subject: | Re: Constraint documentation |
| Date: | 2018-10-30 15:50:13 |
| Message-ID: | 0f600b95-160b-5578-8572-5e49b0fb70a1@francelle.name |
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| Lists: | pgsql-hackers |
On 08/10/18 07:02, Pantelis Theodosiou wrote:
>
> I like this:
>
>> "Postgres does not currently support CHECK constraints containing
> queries, therefore we recommend to avoid them."
>
> Perhaps adding:
>
>> CHECK constraints are currently meant to be used as *row constraints*
> only.
>> Use - if possible - UNIQUE or EXCLUDE constraints. for constraints
> that involve many or all rows of a table,
>> and FOREIGN KEY constraints for cross table constraints.
>> More complex constraints will be available when ASSERTION are implemented.
>
> And then adding some warning about using functions in CHECK constraints
> to bypass current limitations.
>
> Pantelis Theodsoiou
Hi,
I have rewritten the patch to include your remarks.
In fact, the whole patch is now based on it, so thank you.
Patrick Francelle
| Attachment | Content-Type | Size |
|---|---|---|
| check_constraint_accross_table_note_v4.patch | text/x-patch | 874 bytes |
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