| From: | Vik Fearing <vik(dot)fearing(at)dalibo(dot)com> |
|---|---|
| To: | ldrlj1 <russelljanusz(at)yahoo(dot)com> |
| Cc: | pgsql-sql(at)postgresql(dot)org |
| Subject: | Re: table constraint on two columns |
| Date: | 2013-07-22 14:16:43 |
| Message-ID: | 51ED3ECB.5020703@dalibo.com |
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| Thread: | |
| Lists: | pgsql-sql |
On 07/22/2013 04:05 PM, ldrlj1 wrote:
> Postgres 9.2.4.
>
> I have two columns, approved and comments. Approved is a boolean with no
> default value and comments is a character varying (255) and nullable.
>
> I am trying to create a constraint that will not allow a row to be entered
> if approved is set to false and comments is null.
CHECK constraints work on positives, so restate your condition that
way. A row is permissible if approved is true or the comments are not
null, correct? So...
...add constraint chk_comments (approved or comments is not null)...
> This does not work. yada, yada, yada... add constraint "chk_comments' check
> (approved = false and comments is not null). The constraint is successfully
> added, but does not work as I expected.
That's not the same check as what you described.
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