UNIX for Advanced & Expert Users

Hi All,

This question is mainly to get help from u all experts for a database vendor change

we are in the process of migrating our database vendor from INFORMIX to ORACLE to run on SOLARIS 9.4 box.
Hence we need to work out on our applications which all are written in native 4GL (an easy interface to communicate with informix database)

I tried in our forum regarding database vendor change and according effect to the application which uses the database but could not find any such

postings, could be this is the first one of its kind?

As we are going to use ORACLE as our database,
1) Do all the applications written in 4GL have to be necessarily re-written in Pro *C/C++? Is there any other alternatives possible for that?

2) Are there any migration tools avaialable with respect to rewriting applications from 4GL to Pro *C/C++ ?
( I am sure data migration across databases are possible)

3) And above all the risks and feasibility of such kind of a task?

(I am aware that I am piling up questions ...)

Your help would be of great value to me.

I am sure some of you experts would have surely had enough and great real time experience in doing such kind of vendor change and challenges faced during such meticulous migration tasks.

If u experts suggest some good websites, links regarding this it would be even more useful and helpful to me.

Awaiting ur reply.

Thanks.

You can use PL/SQL for procedures and small reports, and ORACLE FORMS for user interface development. Pro*C, Pro*FORTRAN Pro*COBOL are meant for
development of major apps that do a lot of processing and possibly interact with the unix file system. PL/SQL does not do file I/O very well. It has limitations.

PL/SQL is the trigger language.

www.orafaq.org mentions some things about foriegn 4GL's.
I don't know if any of it applies to Informix, because I've worked only with Oracle for 20 years. You can search that site.

You need to do some serious upfront reading. There are some kinds of SQL constructs and dynamic calls that kill Oracle but are common in a lot of apps.

Simple examples of things that may be misused in PL/SQL or SQL in ORACLE:

EXEC IMMEDIATE - creates a dynamic query which looks attractive but for large multiuser systems will eat up resources and reduce throughput. It may chew up caching, for example.

SELECT ... FOR UPDATE can lock an entire table of millions of rows if misused.
I've seen apps that do this, then ask for user input. When the user goes to lunch at this point without pushing the return key, the entire db grinds to a halt as other people need to access that table.

It's a huge book, but will save you endless grief:

Tom Kite 'Expert one on One ORACLE'

There is a version of this book for 8i and 9i. I think he's got a 10g version out, but go here where TOm Kite answers questions, he often lets you know about books out there, you may want to ask him/or search his site to see if there are any resources for porting from Informix - porting is a main part of his expertise:

http://asktom.oracle.com/pls/ask/

thank you so much for your valuable reply Jim.

Let me continue in same thread for any further doubts and clarifications