Path: news.easynews.com!easynews!newshub2.home.com!news.home.com!news.mindspring.net!not-for-mail From: "Steve Kass" 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 10:47:10 -0400 Organization: MindSpring Enterprises Lines: 39 Message-ID: <9q1n6d$qcj$1@slb7.atl.mindspring.net> References: <3bc3da86.56994633@news.compuserve.com> <9q1mmp$19$1@bob.news.rcn.net> NNTP-Posting-Host: a5.f7.3d.41 X-Server-Date: 10 Oct 2001 14:49:49 GMT X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.00.2919.6700 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Xref: easynews microsoft.public.sqlserver.programming:170546 comp.databases.ms-sqlserver:59587 comp.databases.theory:18639 X-Received-Date: Wed, 10 Oct 2001 08:21:03 MST (news.easynews.com) If you want to allow "school not in list" as a possibility, just let student.schoolid be NULL in that case. Steve Kass Drew University "Harlan Messinger" wrote in message news:9q1mmp$19$1@bob.news.rcn.net... > > 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. > > >