Re: MultiValue Databases

From: Neo <neo55592_at_hotmail.com>
Date: 7 Jun 2005 11:42:32 -0700
Message-ID: <1118169752.050726.90610@f14g2000cwb.googlegroups.com>

>> Assume a person can have 0 to many phone numbers. Assume a phone number can be assigned to multiple persons ... normalized the phone numbers to allow adding various attributes to some phone numbers later.

> ... without having read the rest of the thread, ... CREATE TABLE person_phone (char name, char number);

Yes, this could suffice for the initial data. Would it look like this?

Name Number

-------- ----------
John  111-1111
John  222-2222

Mary 222-2222
Bob NULL

What enforces the integrity of the "222-2222"s ? What if "222-2222" appears in mulitple columns of multiple tables? Also when performing a query, should one assume that Bob doesn't have a phone or that he could have a phone and it could be "222-2222"?

> unless you want to record more information about persons and phone numbers, or want to support several persons with the same name

Yes, expect the unexpected. Allow each thing to have any number of attributes and allows each attribute to have any number of values. Allow attributes and values to have their own attributes :) Received on Tue Jun 07 2005 - 13:42:32 CDT