Re: IDS to DB2 conversion

Serge Rielau wrote: > No offense, but you look at this from an ivory-tower's perspective. Hey, you were the one touting the relational aspects of sequences. And I don't know how much more ivory tower you can be than working in a compiler lab. I actually sit in production environments for a living. :o) I've seen the consequences of bad database design and application design, and every one of my clients who has listened to me and fixed those things has seen a remarkable ROI. The ones who bluster about the intractability and opaqueness of their legacy apps are generally deluding themselves. > Reality is not that you start from scratch. > Let's assume a fictive company IBM buys a fictive company IFMX. > Let's further assume IBM runs on DB2 and IFMX on IDS. > Over night a few thousand customers and employees switch hands. > Each company has specialized DBA's all of which would rather leave > their company than betray there favorite DBMS *sound familiar?* I don't know, I've not heard about too many people switching from IDS to DB2, so I don't think this is a relevant point to make. > So what will happen? Long term there may be some alignment, but short > term nothing will change. > The parent company is going to somehow try to integrate this > heterogeneous system. I've heard / seen / implemented a zillion different ways of integrating this stuff. I'm not really sure how federation helps IFMX, because their legacy apps have to be altered anyway. You are talking about rewriting their legacy apps in a way that can be accessed by DB2-compliant SQL and then you might as well redeploy on DB2 anyway. > But it doesn't ahev to be a merger. Just take any major bank. > They run IMS (yes!!), and DB2 for z/Series for sure. > Likely Sybase and Oracle are also in the mix. > All this has nothing to do with what the company's preferred DBMS of the > day is. They cannot move the apps. They are old, they are Cobol and the > developers have long since retired or gone broke in .bomb. So how does federation help the Oracle or Sybase apps access DB2 data? All federation does is allow DB2-compliant apps to read those data sources using a resource-expensive extra layer. Far more efficient to provide a new application accessing the data in a single data source. IBM's assessment that everyone has an unlimited budget to throw at Regattas to provide all this integration doesn't really play below those top banks. > Welcome to reality Not a chance. Remember, Serge, hope is a good thing, maybe the best of things. And no good thing ever dies. (To paraphrase Stephen King :o) -- "C'est pas parce qu'on n'a rien ''' dire qu'il faut fermer sa gueule" - Coluche

OTC, I don't recall having claimed that sequences are a relational feature. It's the admission that purely relational has limits in the real world. Cheers Serge -- Serge Rielau DB2 SQL Compiler Development IBM Toronto Lab

Serge Rielau wrote: > OTC, I don't recall having claimed that sequences are a relational > feature. It's the admission that purely relational has limits in the real > world. Cheers You must live in a different real world than I do. -- "C'est pas parce qu'on n'a rien ' dire qu'il faut fermer sa gueule" - Coluche