Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!asuvax!anasaz!john From: john@anasaz.UUCP (John Moore) Newsgroups: comp.databases Subject: Re: SQL Poser Message-ID: <2385@anasaz.UUCP> Date: 7 Jun 90 02:43:34 GMT References: <6588@umd5.umd.edu> <1990Jun1.132731.6699@oracle.com> <1990Jun4.151555.3479@oracle.com> <2371@anasaz.UUCP> Reply-To: john@anasaz.UUCP (John Moore) Distribution: comp Organization: Anasazi, Inc. Lines: 93 In article cimshop!davidm@uunet.UU.NET (David S. Masterson) writes: ]should eventually be. If past track record holds, 2-3 years from now we'll ]probably have a relational language standard that incorporates OO concepts ](whether it will be called SQL is anyone's guess). My guess also. ]anything) is a clear and complete OO model. Such a model will either supplant ]the relational model (because the relational model will simply be a subset of ]the OO model) or be incorporated into the prevailing model of the time ](because the prevailing model will have the base functionality needed to ]represent the new model). Agreed. ] ]> SQL + RDBMS suffers from many shortcomings, including: ]> (1) Lack of support for truly ordered data. ] ]I still have trouble understanding "truly ordered data". What is it that it ]is not expressed in an "ORDER BY" clause? The relational model works with Yeah... I wonder what I was thinking when I wrote that... Anyway the point below (#2) indicates my real problem with ordering. ]> (2) Lack of the concept of a subset defined by position in an ordered ]> sequence plus count. ] ]The problem I have with this is the time-dependent nature of the subset. ]People usuall desire this capability so that they can close a cursor, go off ]and do other things, and come back to the cursor to pick up where they left ]off. The one question I have is what if the subset changed in between ]accesses (a likely thing in a high transaction environment)? That is, suppose ]what was the fifth item is now the sixth item because a new second item was I suspect different answers suffice for different cases. For example, I use the case of a name lookup, where I can only handle a few at a time. Now, names may be added in that I didn't see before, that would come before (in alpha ordering) the remaining names. I could imagine one customer wanting the new names to show (after all, they do satisfy the initial query conditions), while another might decide that it was too confusing, so they want to just get the next name from the last one displayed. Now, of course, the last one displayed may have disappeared by the time we continue, but this can be handled by backing up the "I'm here" pointer. Cursor options already allow this sort of thing. ]> (3) The previous poster's comment about inability to express a ]> hierarchical query. ] ]This is definitely an area that needs more treatment in relational ]implementations. The relational model seems fully capable of representing ]such concepts, the problem is how to efficiently access such an arrangement ]and return it in a representation that can be dealt with. What does a ]hierarchical set look like? I'm not sure single SQL queries can be written to deal with it. Obviously the data can be stored in a relational database, but perhaps it has to be retrieved by hand (i.e. - do a select, get something, look at it to decide the next select, etc). ] ]> From the standpoint of one who is concerned with performance, I view SQL ]> and RDBMS as designed with NO throught to performance, with indexes sort of ]> tossed in as an afterthought (while collective purists held their noses). ] ]Do you think an OODBMS gives any more thought to performance? Everything I've Sadly enough, they probably don't. But they will in the future. Who knows whether the standards will adopt it. ]Define STANDARDIZATION? How does it differ from MARKET ACCEPTANCE? Is what ]the market accepts the "defacto" standard or are you looking for more in the ]name of standardization (a complete model, something that will last more than ]a couple of years, etc.)? After all, a standard is a standard is a ]standard... A de-facto standard is just fine. All I want is to be able to run my application using several different vendors' product, without rewriting it or making significant changes. ] ]Don't jump too quickly on the OODB bandwagon. There may be nothing wrong with ]OODB, but move too quickly and you may be back in the same boat a couple of ]years from now. Its obvious from your message above that all your "questions" Yep. We jumped on RDBMS when we had to, and at the time there was no product on the market that could meet our needs. However, we anticipated (after talks with vendors, this was informed anticipation ;-) ) that there would be before we went production. We have been working on the project now for 2 years and go production in 5 months. We think we might finally have a vendor product that will work. [I should mention that another of our areas is 24 hr/7 day per week operation. At the time we started, some products didn't allow you to archive the database while it was running]. ]about relational databases have not been answered. Have all your "questions" ]been answered by object oriented databases (both those above and those yet to ]be stated)? (BTW, that's a rhetorical question directed at the group) No! I'll never be completely satisfied with a product in this area. The techno-nerd in me complains that it could be better. The businessman responds that everything could be better, but we have to deal with what we have :-) -- John Moore HAM:NJ7E/CAP:T-Bird 381 {asuvax,mcdphx}!anasaz!john john@anasaz.UUCP Voice: (602) 951-9326 (day or eve) FAX:602-861-7642 Advice: Long palladium, USnail: 7525 Clearwater Pkwy, Scottsdale, AZ 85253 ......: Short petroleum Opinion: Support ALL of the bill of rights, INCLUDING the 2nd amendment!