Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!drn.maxwell.syr.edu!news.maxwell.syr.edu!postnews.google.com!z14g2000cwz.googlegroups.com!not-for-mail From: "birdadderley" Newsgroups: comp.databases.theory Subject: Re: About Entity Relation Diagram Date: 19 Dec 2004 23:10:11 -0800 Organization: http://groups.google.com Lines: 17 Message-ID: <1103526611.766447.256190@z14g2000cwz.googlegroups.com> References: NNTP-Posting-Host: 68.101.148.109 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1103526617 5478 127.0.0.1 (20 Dec 2004 07:10:17 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Mon, 20 Dec 2004 07:10:17 +0000 (UTC) User-Agent: G2/0.2 Complaints-To: groups-abuse@google.com Injection-Info: z14g2000cwz.googlegroups.com; posting-host=68.101.148.109; posting-account=jYLUNA0AAABDjzzM-1aKd-iRsONKtkaO Xref: dp-news.maxwell.syr.edu comp.databases.theory:29104 Well if you wanted to read some theory here on people argue about different database types, well there you have it. Whomever said you shouldn't even be thinking about your schema yet is exactly correct. In the ER diagram you create and brainstorm over, you will eventually convert to tables. If you are thinking about tables in order to create the ER diagram, well theres no point in drawing one up. If you run into problems, bo back to your ER diagram and reorganize; there are probably some relationships that you can clean up/make easier. As far as your table situation mentioned; the PerfectPartner table sounds like a many to many table between members. Therefore at a minimum PerfectPartner should have unique pairs of members.PK -- members.PK sets. (making sure that you apply constraints so that 4 -- 2 is different than 2 -- 4)