Re: Merging 2 "almost" identical databases.

From: hpuxrac <>
Date: Mon, 29 Sep 2008 06:24:31 -0700 (PDT)
Message-ID: <>

On Sep 29, 5:55 am, Neomusashi <> wrote:
> Hi,
> So my work for the next few weeks is sorting out how to merge 2 almost
> identical databases used by 2 almost identical applications into one
> application with one database. These applications were developed for a
> client.
> Why 2 DB' s and 2 Applications? Well it’s a legacy decision. My
> predecessors decided it should be that way and now it ' s up to me to
> fix this. They needed small application/functional differences for
> other distribution channels and made a clone of the original app. .
> Now several years later they would like to merge the two apps into
> one, but of course they grew apart in functionality and structure. No
> big differences, but enough to make this a nice project ... .
> Short description:
> Each application runs on a sun solaris 10 server in a websphere 6.0
> application server (J2EE apps of course) and an orcale 10 database is
> used. Database queries are done using Stored Procedures. Both have 2
> schemas. One schema has the core data in about 20 tables and the other
> contains about 9 generic servers and about tables. The tables purposes
> don’ t really differ from each other, but columns,  DDL and data load
> do.
> What I need to come up with is a merging process we can deliver to our
> client so they can easily merge the two databases.  The process has
> two deliver a clear report.
> I was thinking of three possible ways to go:
> 1.      Shell scripts with logging:
> pros: basic, quickest?
> Cons: Debugging, testing, complex, report/logging not so fancy/clear,
> inhouse expertise
> 2.      Write a mini J2EE app:
> pros: easy to debug, easier to make?, better report/logging
> Cons: very slow to develop, work to throw away.
> 3.      Write a java app:
> pros: easy to debug, easy to make, better report/logging
> cons: work to throw away, slow to develop
> I’ m feeling most for the 3th solution. How would you approach this?

I am guessing that your first decision needs to be whether you will come up with one set of consolidated database tables or if you are going to maintain differences between tables in different schemas.

If you take the perhaps easier route of allowing differences ( still 1 database but in multiple schemas ) then you are just delaying consolidation while hiding some of the differences.

A clean solution probably really calls for one set of tables but then you have to look at column differences etc. Received on Mon Sep 29 2008 - 08:24:31 CDT

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