Re: Examples for one-to-one associations?
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Tue, 08 Jun 2010 10:29:25 -0300
Message-ID: <4c0e45bb$0$11831$9a566e8b_at_news.aliant.net>
Date: Tue, 08 Jun 2010 10:29:25 -0300
Message-ID: <4c0e45bb$0$11831$9a566e8b_at_news.aliant.net>
Keith H Duggar wrote:
> On Jun 7, 2:25 pm, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
>
>>Gene Wirchenko wrote:
>>
>>>On Sat, 5 Jun 2010 20:49:59 -0700 (PDT), hoodwill
>>><chase.saund..._at_gmail.com> wrote:
>>
>>>>Examples of one to ones:
>>
>>>>1) Spouse
>>
>>> You need a time element. Even given monogamy, many people have
>>>been married more than once.
>>
>>Even more basic than that: Some folks are single.
> > Why is that an issue? If a person is single then they would not appear > in the Spouse relation. one-to-one relations can be partial can they > not?
The relative cardinality is 1:zero-or-one not 1:1. Received on Tue Jun 08 2010 - 15:29:25 CEST