> > From: "Paul F" <[EMAIL PROTECTED]> > Date: 2003/11/28 Fri PM 04:35:04 CST > To: "'mysql users'" <[EMAIL PROTECTED]> > Subject: RE: Please analyze my project table design > > > Thanks guys. I thought that normalization would refer to redundant info not > necessarily the same column names? I would further see the problem with the > design if say phone_number in the agent table and lawyer table contained the > same data, which of course they won't.
I agree, which is why I continued to disagree/question the claim of the other posters that the issue is normalization. That being said, regardless of whether the design issue is ascribed to the (important) topic of normalization, what you should do is pretty clear. As Stefan Hinz put it: "All information that is specific for agents only would go to the agent table, and ditto for the lawyer table. All _kinds_ of information both have in common would go to the contact table." > I thought about the "persons" table instead however you might notice that > there are some columns that each do not have. Ie. home and work numbers for > vendors and purchasers, firm for lawyers etc. Also I am expecting several > columns to be NULL values for vendors and purchasers but not the other > persons. Right. But note that the advice of Stefan that I quoted above implicitly addresses these concerns. > I am very concerned with how I have setup the PK/FK/indices! Hmm... Well, PK indices are really not all that hard. FK indices are trickier, insofar as not all versions of MySQL have them implemented. But if you get stumped, just write up a proposed set of table designs (in accordance with the principles Stefan listed), and people here (or at USENET comp.database(s).*, if I recall correctly) would be able to help you. > Thanks guys! > > > > The repeated column names for example phone_number > -----Original Message----- > From: David T-G [mailto:[EMAIL PROTECTED] > Sent: Friday, November 28, 2003 3:49 PM > To: mysql users > Cc: [EMAIL PROTECTED] > Subject: Re: Please analyze my project table design > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi! > > ...and then [EMAIL PROTECTED] said... > % > ... > % I don't know of a DB theory rule that says it's a bad idea to have the > same columns in many tables, but it might make the design more compact to > take the common stuff and put it into one table. > > Oh, there is, indeed. CF "normalization" :-) > > > HTH & HAND & good luck Paul > > :-D > - -- > David T-G * There is too much animal courage in > (play) [EMAIL PROTECTED] * society and not sufficient moral courage. > (work) [EMAIL PROTECTED] -- Mary Baker Eddy, "Science and Health" > http://justpickone.org/davidtg/ Shpx gur Pbzzhavpngvbaf Qrprapl Npg! > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.0.7 (FreeBSD) > > iD8DBQE/x8LcGb7uCXufRwARAq2vAKCDgl6tAoZyQMxRcuweK4fPFO8flQCfT1QU > pJXdxLO02cnospbngiqMqzI= > =eKBn > -----END PGP SIGNATURE----- > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
