I have got a problem in data migration. Basically I want to do following steps.

1. I need to send one value to Oracle on Unix from following databases. MS Access, MS SQL Server on windows 2000, Oracle on Windows 2000.
2. In return I need to get a value from Oracle on Unix.
3. Store the returned value in the local database like MS Access/ MS SQL Server on windows 200/ Oracle on windows 2000.

Can I do this just by writing some SQL and PL/SQL scripts ?