Search Postgresql Archives

Re: Best way to allow column to initially be null?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Glen Huang wrote:
> I’m trying to make a column have these properties:
>
> 1. When a row is inserted, this column is allowed to be null. 2. When the row is updated, no null
> can be assigned to it this column.
>
> I initially thought I can drop the not null constraint before insertion and turn it back on after
> that, but after reading the doc it seems turning on not null constraint requires not columns
> contain null value, so looks like it won’t work.
>
> My current approach is to not set the not null constraint in the table and use a before update
> trigger to manually raise exception when the column is null. But it doesn’t seem as elegant.
>
> Is there a better way?
>

Sounds to me like a BEFORE UPDATE trigger is exactly the way to handle this. Rejecting invalid data input values is an ideal use case for such a facility.


--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]

  Powered by Linux