Re: Problems faced during migration from Informix to oracle

Triveni wrote: > Hi, > Can you pl let me know what are the problems that where faced while > migrating database from informix to oracle. > > > Regards, > Triveni Migrating data is reasonably simple and both IBM and Oracle, as well as third-party vendors, provide a wide array of decent tools. The biggest issue is in moving code as the underlying paradigms of the two databases are completely different as well as the verbiage. So you will find that basic words like 'database' can have very different meanings. The code issues revolve around the fact that the Oracle kernel supports multiversion read consistency control (MVCC) which, in short, means that reads don't block writes and writes don't block reads. The structures necessary to support this are drastically different from that of a kernel where the consistency is achieved through locking. If you are seriously looking at this pick up a copy of Tom Kyte's book "Expert one-on-one Oracle" and pay especially close attention to the first three chapters. -- Daniel A. Morgan University of Washington damorgan@x.washington.edu (replace 'x' with 'u' to respond)