Re: Is a SERIAL column a "black box", or not?

On Sat, 2006-04-29 at 17:54 -0400, Tom Lane wrote:
> In some recent activity on the patches list about responding to bug #2073,
> http://archives.postgresql.org/pgsql-bugs/2005-11/msg00303.php
> we've been discussing various possible tweaks to the behavior of dropping
> or modifying a serial column.  The hacks involved with SERIAL seem to me
> to be getting uglier and uglier, and I think it's time to take a step
> back and consider what we really want SERIAL to act like.
> 
> It seems to me there are two basic philosophies at war here:
> 
> 1. A serial column is a "black box" that you're not supposed to muck with
> the innards of.


> 2. A serial declaration is just a "macro" for setting up a sequence and a
> column default expression.  This was the original viewpoint and indeed is
> still what it says in the documentation:

> Comments, other opinions?

Do both. Return SERIAL to being a macro and implement the SQL IDENTITY
construct as the black box version.
       CREATE TABLE foo (bar integer PRIMARY KEY GENERATED BY DEFAULT       AS IDENTITY);

INSERT ... RETURNS needs to be implemented before SERIAL can become a
black box. Until that time we will still need some knowledge of the
sequence involved.

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