Re: RE: Any articles/books that take relational theory and make it
how does dimensional modelling used by datawarehousing fit into relational theory? From: Daniel Hanks [EMAIL PROTECTED] Date: 2003/11/19 Wed PM 04:35:03 EST To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Subject: RE: Any articles/books that take relational theory and make it Agreed. And I think you'll admit it's better to be familiar with and aware of the theory, even if current db products don't live up to the model 100%, so you know to bring up the kinds of issues you mention in the first place. In that sense, I think the knowledge to be gained from Date, Darwen, Pascal, etc., can be very practical. -- Dan On Wed, 19 Nov 2003, Niall Litchfield wrote: I obviously can't speak for the list, but I find Fabian Pascal to be very interesting, but quite academic. What I *think* that I mean by this is that a lot of what he says seems to make theoretical sense, but I'm unsure how applicable it is to practice. IOW the general feel that I get from Fabian (and indeed Date) is that if something doesn't meet relational theory then it is flawed. This may well be a good default position to have, but I'm unprepared to say to folk who pay my wages 'sorry your data model isn't in 3NF' or 'you shall not use a materialized view'. I *will* quite happily say 'so how will you ensure data integrity?' 'what happens if another program uses the same data' or 'why did you use computed summaries?' Niall -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Daniel Hanks Sent: 19 November 2003 16:25 To: Multiple recipients of list ORACLE-L Subject: Re: Any articles/books that take relational theory and make it On Wed, 19 Nov 2003 [EMAIL PROTECTED] wrote: I swapped emails with a member of the list and Im having trouble seeing how you can take 3NF, BCNF, etc... and turn that into DBA speak. One of the guys told me that BCNF essentially means you have a key that you can put a unique constraint on. Well that makes this much easier to understand. Hrm, I thought a key, by definition, implied a unique constraint... All my theory books just discuss theory. Anyone know some that split the difference. IE, not Codd, not CJ Date, Not the academic textbooks. I'm not sure what the opinion on Fabian Pascal is here on the list, but I found his Practical issues in Database Management to be very good. It's subtitled A reference for the thinking practitioner. It's not a textbook, but it does make you use your brain a bit. It might be what you're looking for. It has helped to clarify the relational model for me, but might put some people off as it's critical (without naming specific products) of most current implementations of 'relational' databases. Thanks. -- Dan == == Daniel Hanks - Systems/Database Administrator About Inc., Web Services Division == == -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Daniel Hanks INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Daniel Hanks - Systems/Database Administrator About Inc., Web Services Division -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Daniel Hanks INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: [EMAIL PROTECTED] INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http
Re: Re: Any articles/books that take relational theory and make it
there are used copies for sale right on there. From: KENNETH JANUSZ [EMAIL PROTECTED] Date: 2003/11/20 Thu AM 11:20:15 EST To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Subject: Re: Any articles/books that take relational theory and make it Unfortunately according to Amazon.com this book is out of print. Ken Janusz, CPIM - Original Message - To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Sent: Wednesday, November 19, 2003 8:40 AM Data Modeling Essentials by Graeme C Simsion is a very good book. American Express made the following annotations on 11/19/2003 07:36:46 AM -- ** This message and any attachments are solely for the intended recipient and may contain confidential or privileged information. If you are not the intended recipient, any disclosure, copying, use, or distribution of the information included in this message and any attachments is prohibited. If you have received this communication in error, please notify us by reply e-mail and immediately and permanently delete this message and any attachments. Thank you. ** == -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Tracy Rahmlow INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: KENNETH JANUSZ INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: [EMAIL PROTECTED] INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: RE: Any articles/books that take relational theory and make it
Well, Pascal has this to say about it: http://www.dbdebunk.com/page/page/622521.htm (This also links to some comments by Date on some articles by Ralph Kimball). What it comes down to for me is this, the relational model provides a way (by being based on set theory and predicate logic) to ensure that your query results are mathematically sound, and thus you can trust your data. To paraphrase Pascal, a database is simply a set of axioms, which we can use (via queries) to form proofs about various aspects of our enterprise. If we ensure our data is normalized, and ensure that appropriate constraints are in place, we can trust that the axioms we store in the database are valid, and that our 'proofs' are also accurate, and ultiumately we can trust the information we are getting out of the database. Again, I'd recommend Pascal's book, 'Practical issues...' as he explains these things more clearly than I can. Granted our bosses/managers/clients, etc., may not be interested in hearing about normalization and predicate logic, but I think they do put value in having accurate data with which to pursure business interests. Being aware of the theoretical issues associated with the relational model can only help in our position as 'guardians of the data'. Fwiw, -- Dan On Thu, 20 Nov 2003 [EMAIL PROTECTED] wrote: how does dimensional modelling used by datawarehousing fit into relational theory? From: Daniel Hanks [EMAIL PROTECTED] Date: 2003/11/19 Wed PM 04:35:03 EST To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Subject: RE: Any articles/books that take relational theory and make it Agreed. And I think you'll admit it's better to be familiar with and aware of the theory, even if current db products don't live up to the model 100%, so you know to bring up the kinds of issues you mention in the first place. In that sense, I think the knowledge to be gained from Date, Darwen, Pascal, etc., can be very practical. -- Dan On Wed, 19 Nov 2003, Niall Litchfield wrote: I obviously can't speak for the list, but I find Fabian Pascal to be very interesting, but quite academic. What I *think* that I mean by this is that a lot of what he says seems to make theoretical sense, but I'm unsure how applicable it is to practice. IOW the general feel that I get from Fabian (and indeed Date) is that if something doesn't meet relational theory then it is flawed. This may well be a good default position to have, but I'm unprepared to say to folk who pay my wages 'sorry your data model isn't in 3NF' or 'you shall not use a materialized view'. I *will* quite happily say 'so how will you ensure data integrity?' 'what happens if another program uses the same data' or 'why did you use computed summaries?' Niall -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Daniel Hanks Sent: 19 November 2003 16:25 To: Multiple recipients of list ORACLE-L Subject: Re: Any articles/books that take relational theory and make it On Wed, 19 Nov 2003 [EMAIL PROTECTED] wrote: I swapped emails with a member of the list and Im having trouble seeing how you can take 3NF, BCNF, etc... and turn that into DBA speak. One of the guys told me that BCNF essentially means you have a key that you can put a unique constraint on. Well that makes this much easier to understand. Hrm, I thought a key, by definition, implied a unique constraint... All my theory books just discuss theory. Anyone know some that split the difference. IE, not Codd, not CJ Date, Not the academic textbooks. I'm not sure what the opinion on Fabian Pascal is here on the list, but I found his Practical issues in Database Management to be very good. It's subtitled A reference for the thinking practitioner. It's not a textbook, but it does make you use your brain a bit. It might be what you're looking for. It has helped to clarify the relational model for me, but might put some people off as it's critical (without naming specific products) of most current implementations of 'relational' databases. Thanks. -- Dan == == Daniel Hanks - Systems/Database Administrator About Inc., Web Services Division == == -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Daniel Hanks INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself
Re: RE: Any articles/books that take relational theory and make it
which noted O-O author said that about DBs? From: DENNIS WILLIAMS [EMAIL PROTECTED] Date: 2003/11/20 Thu PM 02:59:58 EST To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Subject: RE: Any articles/books that take relational theory and make it Paula - It may get worse. A noted O-O author said a database is just a means to persist an object. I also see a lot of young developers that haven't taken much Computer Science, so haven't been exposed to underlying theories like relational modeling. Well, we DBAs just have to be lights shining into the darkness. Dennis Williams DBA Lifetouch, Inc. [EMAIL PROTECTED] -Original Message- [mailto:[EMAIL PROTECTED] Sent: Thursday, November 20, 2003 12:45 PM To: Multiple recipients of list ORACLE-L Why in an IT shop - do us DBA's only seem to understand this? As I see it most programmers don't understanding data models at all! It makes it easier for them to ignore the DBA's as being theoretical, academic -Original Message- Sent: Thursday, November 20, 2003 1:30 PM To: Multiple recipients of list ORACLE-L Hear, hear! pb --- Michael Milligan [EMAIL PROTECTED] wrote: As Date is want to say, Theory is practical! (Chapter One, Relational Database Writings 1991-1994). IMHO, a lack of understanding of relational database theory leads directly to database designs so flawed that they can't possibly allow their application to accomplish their goals. If you don't think in terms of functional dependencies, if you don't know the trade-offs in using nulls, if you don't why you want to put some attributes in one entity and others in others, you'll be in trouble. Some people call all of this theory. I see it as the fundamental principles that you'll be dead in the water without. If you don't know what the relational in RDBMS means (nothing to do with foreign keys), you'll make a bunch of mistakes over and over, knowing something is wrong but not able to put your finger on what's wrong. Then you'll limp along with an unfixable application, held together with prayers, and not able to deliver performance or even the right data. I've been doing this for 17 years and I've seen it happen more times than I like to remember. My suggestion, my strong suggestion, is to learn the theory to such an extent that you'll know why a model is good or why it's flawed. If you don't know what a good model is, how can you possibly create one? Data modeling is hard work. There is no shortcut for it. There is also no shortcut for learning it. But you can learn from people who understand it well and can express it well, also. In my opinion, those names include C.J. Date, Hugh Darwen, Fabian Pascal, and a number of others. HTH Michael Milligan Oracle DBA Ingenix, Inc. 2525 Lake Park Blvd. Salt Lake City, Utah 84120 wrk 801-982-3081 mbl 801-628-6058 [EMAIL PROTECTED] -Original Message- Sent: Wednesday, November 19, 2003 2:35 PM To: Multiple recipients of list ORACLE-L Agreed. And I think you'll admit it's better to be familiar with and aware of the theory, even if current db products don't live up to the model 100%, so you know to bring up the kinds of issues you mention in the first place. In that sense, I think the knowledge to be gained from Date, Darwen, Pascal, etc., can be very practical. This e-mail, including attachments, may include confidential and/or proprietary information, and may be used only by the person or entity to which it is addressed. If the reader of this e-mail is not the intended recipient or his or her authorized agent, the reader is hereby notified that any dissemination, distribution or copying of this e-mail is prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and delete this e-mail immediately. -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Michael Milligan INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do you Yahoo!? Free Pop-Up Blocker - Get it now http://companion.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Paul Baumgartel INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http
