Re: Multiple parent design

Some people may object to my previous suggestion, because it relies on NULLS. Here's an alternative:

Take the parent_id out of the phone table.

Create two new tables:

create table PERSONAL_PHONE
  (PHONE_ID,
   PERSON_ID); create table COMPANY_PHONE
  (PHONE_ID,
    COMPANY_ID); Put in the appropriate constraints for referential integrity, and relationships. A PHONE_ID must exist in one and only one of these two tables.

"Laconic2" <laconic2_at_comcast.net> wrote in message news:64GdnYurVfsYVOLdRVn-sQ_at_comcast.com...
> Create two columns in the phone table, Person_id and Company_id. Enforce
> referential integrity on each one separately. Allow each one to be NULL.
>
> If necessary, enforce a constraint that either Person_id or Company_id
must
> be null.
>
>
Received on Fri Apr 16 2004 - 07:26:24 CDT