Let's say I got a database A filled with lots of tables and content of all sorts. And I got a database B, which is somewhat similar to A, but has a slightly different structure. I now want to move the contents of database A into database B.

My question is: does anyone happen to know a tool or something, where I can set up some rules, that make this migration process run smooth without any problems? Like, where I could tell the tool something such as "if table name = XYZ then add a new field to each index". Just a way that lets me define on how to deal with the slight structural differences between the two databases.

Thanks for any help.