Path: news.easynews.com!easynews!newshub2.home.com!news.home.com!howland.erols.net!feed2.news.rcn.net!feed1.news.rcn.net!rcn!not-for-mail From: "Harlan Messinger" Newsgroups: microsoft.public.sqlserver.programming,comp.databases.ms-sqlserver,comp.databases.theory Subject: Re: How to prevent updates on foreign key default values Date: Wed, 10 Oct 2001 10:41:40 -0400 Lines: 27 Message-ID: <9q1mmp$19$1@bob.news.rcn.net> References: <3bc3da86.56994633@news.compuserve.com> Reply-To: "Harlan Messinger" X-Trace: UmFuZG9tSVbKoIlQXT7IK59GCQVVv/QDZnUPeH8cXFJWM/y54jesbOKzCPhXqBCK7gDCjoqSa8w= X-Complaints-To: abuse@rcn.com NNTP-Posting-Date: 10 Oct 2001 14:41:29 GMT X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4807.1700 X-Priority: 3 X-Newsreader: Microsoft Outlook Express 5.50.4807.1700 X-MSMail-Priority: Normal Xref: easynews microsoft.public.sqlserver.programming:170544 comp.databases.ms-sqlserver:59585 comp.databases.theory:18638 X-Received-Date: Wed, 10 Oct 2001 08:15:45 MST (news.easynews.com) wrote in message news:3bc3da86.56994633@news.compuserve.com... > On 07 Oct 2001 17:46:32 +0200, Christoffer Vig > wrote: > >Now what happens if the first thing I do in this database is > >register a new student? ( ie. no school has yet been registered) > > Register a new student for what? In the absence of a school, that > doesn't make sense to me. A student without a school isn't a student. He is a student if "without a school" means "the school hasn't been entered in the database *yet*". Imagine you're a data entry clerk at a large foundation that provides research grants to graduate students. You're entering one student's application and find that his school isn't listed in the drop-down list/combo box from which you are supposed to select the student's school. You're not the person responsible for entering schools into the system. Assuming that systems are supposed to reflect the uses to which they are put, rather than use cases being rearranged to suit pure computational theory, it would seem that the data entry application would have to provide a way to indicate "school not in list" for this student. Certainly it will be someone else's job to scan the data periodically for schools that need to be newly entered, and update the records for those students after that has happened.