Re: Constraint documentation

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
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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


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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