On Tue, 2007-04-24 at 05:39 -0600, Pat Maddox wrote:
> I want to start using slony for replication, and have a question about
> setting table IDs when creating replication sets.  The docs say that
> you have to be careful in what IDs you assign to the tables - if
> there's a relationship between two tables, the parent needs to have a
> lower ID.
> 
> So let's take two tables, users and articles.
> 
> Users:
> id serial primary key
> name varchar(80)
> 
> Articles:
> id serial primary key
> title varchar(80)
> body text
> user_id (foreign key on users.id)
> 
> If I'm using slony to replicate this db, then I need to give the users
> table an id of 1, and articles should be 2, right?

Correct.

> What happens when I add a table that's higher up on the heirarchy?
> For example now I want to add a companies table.
>
>
> Companis:
> id serial primary key
> name varchar(80)
> 
> Users:
> company_id (fkey on companies.id)
> 
> Now would I have to reassign IDs for the tables?  companies->1,
> users->2, articles->3?

That would be one way of doing it.  You would have to drop these tables
from replication and re-add them with the new id's though.

If this scenario is one that you expect to face, I'd recommend leaving
gaps in your table id's so you can plug things in later without having
to do this.

-- 
Brad Nicholson  416-673-4106
Database Administrator, Afilias Canada Corp.