Since you are already at the DB level (outside of cayenne) making this
change, I would just use a BEFORE UPDATE row-level trigger in Postgres. You
can change the value there.
Something like this would work:
CREATE OR REPLACE FUNCTION company_default()
RETURNS trigger AS $$
BEGIN
NEW.company = coalesce(NEW.company, <some default>);
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER mytable_update
BEFORE UPDATE ON MyTable
FOR EACH ROW
WHEN (NEW.company IS NULL)
EXECUTE FUNCTION company_default();
On Tue, Sep 8, 2020 at 3:13 PM Hugi Thordarson <[email protected]> wrote:
> Working with old DB designs really results in the weirdest questions…
>
> So… I've been working around a design problem in a customer DB by using my
> own BatchTranslatorFactory. The functionality was that if a column is
> called "company", every update wraps the column's new value in a coalesce
> function to ensure that it's never set to null (for… reasons). This has
> worked great as a workaround for our problem.
>
> However, SQL generation in Cayenne 4.2 is all new so my current solution (
> https://gist.github.com/hugith/a33a20fc7da7fd8f709f59ce3a30a96a <
> https://gist.github.com/hugith/a33a20fc7da7fd8f709f59ce3a30a96a> )
> doesn't really port.
> Before I start considering migration to 4.2, is this possible to do there?
> Or should I just bite the bullet and start fixing up that bloody DB before
> upgrading?
>
> Cheers,
> - hugi
