Re: use null or 0 in foreign key column, to mean "no value"?

> On 27 Jun 2015, at 5:59, Robert Nikander <rob(dot)nikander(at)gmail(dot)com> wrote:
> In application code, prepared statements want to say: `select * from items where color_id = ?` and that `?` might be a int or null, so that doesn’t work.

You could add another parameter to test which expression to 'activate' in the query, something like:

select * from items where ('notnull' = ? and color_id = ?) or ('null' = ? and color_id is null);

Of course, with those _positional_ query parameters that means you need to add the same value TWICE into the query. You wouldn't need to with _named_ query parameters, if those are available to you.

Alban Hertroys
--
If you can't see the forest for the trees,
cut the trees and you'll find there is no forest.