Question about database integration

[oracle_dba12]

Hello,

I am new to this whole database integration and would like to get any help on this ! We have multiple oracle databases and we will like to integrate all in one if possible.

Can anyone answer these questions:

1) What are the different approaches for database integration ?
2) What to look for before deciding which approach to take ?
3) Any references/ books that might help

Thank you for your help
neil

[marist89]

By Integration, I think you are talking about taking instances from lots of little machines and moving them onto one big machine. To me, this is consolidation.

There are two schools of thought on this subject. Some very well respected people (ie. Tom Kyte) believe that each machine should have one instance. The advantage is that sharing data is easier and you need less overall resources to manage one instance over two. I'm not one to put words in Tom Kyte's mouth, so you can read about it here . In this method, each database you are trying to consolidate would have it's own schema in one big monster database.

Some not-so-respected people (myself included) believe that provided you have enough resources, you can run multiple instances on the same machine. By all means, put the data in the same database is it functionally makes sense, but otherwise leave it in it's own instance. If you think the database will undergo tremendous growth and might have to be moved to a seperate server, IMHO, it's much easier to move a large database than a large schema. Also, it gives you the opportunity to tune the two databases for different transaction types. In addition, it's less changes to move an instance from machineA to machineB come monday morning when your users report "things are slow".

Unfortunately, there's no one right answer to your question. In fact, your ideal solution might be a mix of the two ideas.