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So, what you're saying Michael is that native I/O is a 30 year old technique, and is akin to RPG II? Whereas, if you want to be 'modern' you must use SQL or Join Logicals? Hmm. Let me think about that for a while. Thanks, Mark Mark D. Walter Senior Programmer/Analyst CCX, Inc. mwalter@xxxxxxxxxx http://www.ccxinc.com michael@ryantechn ology.com Sent by: To midrange-l-bounce Midrange Systems Technical s@xxxxxxxxxxxx Discussion <midrange-l@xxxxxxxxxxxx> cc 05/03/2005 03:08 PM Subject RE: Normalization was Left AS/400 and Returned Please respond to Midrange Systems Technical Discussion <midrange-l@midra nge.com> Of course, a lot of RPG programmers don't use join logicals. Instead, they provide their own indexed file navigation by getting a value from one file, using that value to chain to another file, getting value from that file, chaining to another file...and on and on. There's a divide in AS/400-land...those that can/will use SQL or join logicals and want a normalized database, and those who have a series of indexed files and do their own navigation. Basically, if a programmer wants to use more modern techniques, the iSeries can support them. And of course, if a programmer still wants to code in RPG/II, they can. The ability to use 30 year old techniques is a 'feature' on the iSeries. > -------- Original Message -------- > Subject: Re: Normalization was Left AS/400 and Returned > From: rob@xxxxxxxxx > Date: Tue, May 03, 2005 2:55 pm > To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx> > > I agree on the multi-format and join logical files. Or, SQL's views. And > highly recommend them for programming, and, most especially, for common > links the users use in Queries instead of having them join multiple files > together. > > However, he might be right about the performance issue. For example, > which would access faster: > 1 - A key over customer number and part number in a de-normalized > order/line file. > 2 - A join logical that joins the order/header file with the order/line > file so that you can see the customer number from the order header file at > the same time you see the part number of the order line file. And, keep > in mind, that a join logical file does not allow keys from more than one > file, even though I suspect every new release of OS/400 has formed yet > another DCR requesting this feature. This might be possible with an index > on a view in SQL but I don't think that's allowed either. I know you can > get the data this way in a normalized database via SQL but it's going to > do some work under the covers and performance may suffer. > > Rob Berendt > -- > Group Dekko Services, LLC > Dept 01.073 > PO Box 2000 > Dock 108 > 6928N 400E > Kendallville, IN 46755 > http://www.dekko.com > > > > > > "Bill Meecham" <bmeecham@xxxxxxxxxxxxxxxxxxxx> > Sent by: midrange-l-bounces@xxxxxxxxxxxx > 05/03/2005 01:33 PM > Please respond to > Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx> > > > To > "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx> > cc > > Subject > Re: Left AS/400 and Returned > > > > > > > That's not necessarily true since multi-format and join logical files can > be created and created much easier when the database is normalized. The > reason shops don't normalize is more likely because it's difficult to > master and there is little perceived benefit. Borrowing from another > thread, that's a large part of what case tools help with....normalization > and 'virtualization' of fields. > ----- Original Message ----- > From: michael@xxxxxxxxxxxxxxxxxx > To: Midrange Systems Technical Discussion > Sent: Tuesday, May 03, 2005 2:25 PM > Subject: RE: Left AS/400 and Returned > > > The reason that most vendors and shops don't have normalized databases > is because most vendors and shops don't use the data store on the > iSeries as a database - it's used as a system of indexed files. > Normalization in that scenario can hurt performance, because the > program would need to chain to several files to gather the information > needed to present to the user. There's no doubt that normalization is a > good thing for a database (at least 3NF), but normalization for indexed > files isn't as important or desired. > > -- > This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing > list > To post a message email: MIDRANGE-L@xxxxxxxxxxxx > To subscribe, unsubscribe, or change list options, > visit: http://lists.midrange.com/mailman/listinfo/midrange-l > or email: MIDRANGE-L-request@xxxxxxxxxxxx > Before posting, please take a moment to review the archives > at http://archive.midrange.com/midrange-l. > > > -- > This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list > To post a message email: MIDRANGE-L@xxxxxxxxxxxx > To subscribe, unsubscribe, or change list options, > visit: http://lists.midrange.com/mailman/listinfo/midrange-l > or email: MIDRANGE-L-request@xxxxxxxxxxxx > Before posting, please take a moment to review the archives > at http://archive.midrange.com/midrange-l. -- This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list To post a message email: MIDRANGE-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options, visit: http://lists.midrange.com/mailman/listinfo/midrange-l or email: MIDRANGE-L-request@xxxxxxxxxxxx Before posting, please take a moment to review the archives at http://archive.midrange.com/midrange-l.
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