Re: WIP: extensible enums

On 8/23/10 12:20 PM, Tom Lane wrote:
> Josh Berkus <josh(at)agliodbs(dot)com> writes:
>> I really don't see the value in making a command substantially less
>> intuitive in order to avoid a single keyword, unless it affects areas of
>> Postgres outside of this particular command.
>
> It's the three variants to do two things that I find unintuitive.

Actually, it's 3 different things:

1. BEFORE adds a value before the value cited.
2. AFTER adds a value after the value cited.
3. unqualified adds a value at the end.

The fact that AFTER allows you to add a value at the end is
circumstantial overlap. While executing an AFTER, you wouldn't *know*
that you were adding it to the end, necessarily.

The other reason to have AFTER is that, in scripts, the user may not
have the before value handy due to context (i.e. dynamically building an
enum).

Anyway, this'll still be useful with BEFORE only. I'm just convinced
that we'll end up adding AFTER in 9.2 or 9.3 after we get a bunch of
user complaints and questions. So why not add it now?

--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com