Обсуждение: Re: [HACKERS] inherited sequences and primary keys

>
>I've got a table that has a primary key with a default of
>nextval('seq').  I've got another table which inherits this one, but
>it fails to inherit the unique btree index.  It does inherit the
>default value.  So, I'm assuming that if I create a unique index for
>that field on the child table, it won't keep you from inserting values
>that exist in that field in the parent table (and since they both
>share the same sequence, that's what I want).
This is the way it should work IMO.
>
>So primary keys do not work in this situation.  Are there plans to
>enhance the inheritance?  I have no idea how it works, is it
>intelligent?  Seems more klunky than not, but I haven't really looked
>at the code.  Should I stop using inheritance altogether, considering
>its drawbacks (no idea what child class it is in when selecting from
>parent and all children, no shared indices/pkeys) when I don't select
>from them all at once?

IMO the current semantics for inheritance in Postgresql are broken.
I've been wanting to do something about it but I got distracted and started
to debug some other problems in the system.

I hope to get back to this some time.

I personally feel that we have to make some choices:

    Is postgresql going to be an Object Relational dbms or is it going to
    be yet another relation dbms?

When the developers make an explicite choice on this point it will be a
Good Thing (tm).


With regards from Maurice.

Maurice:
> IMO the current semantics for inheritance in Postgresql are broken.

It seems that way.

> I've been wanting to do something about it but I got distracted and started
> to debug some other problems in the system.
>
> I hope to get back to this some time.
>
> I personally feel that we have to make some choices:
>
>     Is postgresql going to be an Object Relational dbms or is it going to
>     be yet another relation dbms?
>
> When the developers make an explicite choice on this point it will be a
> Good Thing (tm).

Agreed. There are lots of pretty decent relation dbms's out there. There are
very few Object Relational dbms's. I happen to think ORDBMS is a really cool
idea and have seen some great applications done with it that a straight
up RDBMS just couldn't do. So my vote is for ORDBMS.

That said, postgresql needs to become a much better RDBMS that it currently
is.

-dg

David Gould            dg@illustra.com           510.628.3783 or 510.305.9468
Informix Software  (No, really)         300 Lakeside Drive  Oakland, CA 94612
 - Linux. Not because it is free. Because it is better.

David Gould wrote:
>
> Agreed. There are lots of pretty decent relation dbms's out there. There are
> very few Object Relational dbms's. I happen to think ORDBMS is a really cool
> idea and have seen some great applications done with it that a straight
> up RDBMS just couldn't do. So my vote is for ORDBMS.
>
> That said, postgresql needs to become a much better RDBMS that it currently
> is.

Agreed.
Unfortunately, there are many problems in all areas of postgres.
And time is limited :(

Vadim