Re: Re: Changing the default value of an inherited column

On Fri, Mar 30, 2001 at 12:10:59PM -0500, Tom Lane wrote:
> Comments?  I'm going to implement and commit this today unless I hear
> loud squawks ...

I like it in general and I think it opens some interesting
possibilities.  I don't know much about how the inheritance system is
implemented, so I will put out this scenario in case it makes a
difference.

We recently decided to refactor our schema a bit, using inheritance.
All of our tables have a primary key called "seq" along with some
other common fields such as entry time, etc.  We realized that moving
them into a "base" table allowed us to create functions on "base"
that would work on every derived table.  The main problem was that
we needed fields like "seq" to have distinct sequences, which was
not possible without the ability to override the default value in
each derived table.  It seems like this would be easily doable with
this change.

Another thing that seems kind of interesting would be to have:

CREATE TABLE base (table_id CHAR(8) NOT NULL [, etc.]);
CREATE TABLE foo  (table_id CHAR(8) NOT NULL DEFAULT 'foo');
CREATE TABLE bar  (table_id CHAR(8) NOT NULL DEFAULT 'foo');

Then a function on "base" could look at table_id and know which
table it's working on.  A waste of space, but I can think of
uses for it.
-- 
Christopher Masto         Senior Network Monkey      NetMonger Communications
chris@netmonger.net        info@netmonger.net        http://www.netmonger.net

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