Re: Check constraints do not seem to be working!!!
От
Nikolay Samokhvalov
Тема
Re: Check constraints do not seem to be working!!!
Дата
Msg-id
CANNMO+L_8KePx6Svj2kFOd1RHnWZTMy7_-KXq+sJDHLM8gPinw@mail.gmail.com
Ответ на
Check constraints do not seem to be working!!! (Jitendra Loyal)
Список
Дерево обсуждения
Check constraints do not seem to be working!!! Jitendra Loyal <jitendra.loyal@gmail.com>
Re: Check constraints do not seem to be working!!! Chris Sterritt <chris.sterritt@yobota.xyz>
Re: Check constraints do not seem to be working!!! Pavel Stehule <pavel.stehule@gmail.com>
Re: Check constraints do not seem to be working!!! Nikolay Samokhvalov <samokhvalov@gmail.com>
Re: Check constraints do not seem to be working!!! Jitendra Loyal <jitendra.loyal@gmail.com>
Re: Check constraints do not seem to be working!!! Tomas Vondra <tomas.vondra@enterprisedb.com>
Re: Check constraints do not seem to be working!!! Laurenz Albe <laurenz.albe@cybertec.at>
Re: Check constraints do not seem to be working!!! Jitendra Loyal <jitendra.loyal@gmail.com>
Re: Check constraints do not seem to be working!!! Jitendra Loyal <jitendra.loyal@gmail.com>
Re: Check constraints do not seem to be working!!! Alban Hertroys <haramrae@gmail.com>
On Wed, Nov 11, 2020 at 12:26 AM Jitendra Loyal <jitendra.loyal@gmail.com> wrote:
Despite the above two constraints, the following rows get into the table:
insert into t (b , c) values (null, true), (null, false);
This behavior is described in the docs https://www.postgresql.org/docs/current/ddl-constraints.html#DDL-CONSTRAINTS-CHECK-CONSTRAINTS:
> It should be noted that a check constraint is satisfied if the check expression evaluates to true or the null value. Since most expressions will evaluate to the null value if any operand is null, they will not prevent null values in the constrained columns. To ensure that a column does not contain null values, the not-null constraint described in the next section can be used.
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