Are heterogeneous database systems in practice?

Question

Hi,

I was probing around a bit in the realm of databases and hit the notion of having heterogeneous databases. I googled and found this - link text

My question is what kind of scenario would put this into practice and is it really useful? Is it just another thing which was thought about but not implemented or in case it was implemented, then it got restricted to a very niche area?

cheers

Answer 1

I would say yes, very much so. One implementation I am familiar with is integrating MAS90 with an LOB production system. The data is duplicated in both but accessed and used in different ways.

Answer 2

I've worked on a heterogeneous system before. It's a commercial system to manage study abroad programs for large universities, and they had installations on Oracle, MySql, and Sql Server. I was an outside consultant handling a very specific conversion project, though, so I didn't get to see many of the issues involved in making it work well everywhere.

I do remember that the single biggest hurdle I had to deal with was Oracle's lack of a simple autoincrement-style column and having to set up separate sequences instead. There were a number of datatype mismatches as well, but there was a pretty good system in place to just map those.

Note that even here, each customer only had one kind of database. We didn't have to worry about replicating data itself between db types (aside from a few common lookup tables). Just structure.

Answer 3

Different departments in your company might use different databases. I pull data in and push data to from the following

SQL Server

Oracle

Sybase IQ

Access

MySQL

FoxPro

Flat files

Excel files

The SQL Server database is the repository off all the data but it pull from many different databases to populate data and then data will be pushed to different databases for departmental use