Data migration between different DBMS's

Question

As i couldnt get any satisfying answer to my Question it seems we have to write our own program for that, we are in the design phase and we are thinking which format shall w

Answer 1

If you have to export metadata too and not only data, it could be very complex. There are many subtle (and not so subtle differences) among the databases you're going to use, that such a format should be general enough and the exporting/importing code should be able to translate and map metadata across databases, and because an external application can't write directly to the database internal structures, it would have to generate the db proper DDL to create the data structures. As long as this is a proprietary format, IMHO its design is the least of your issues, if size and performance are important and the file is read sequentially it would not be difficult to design a binary format. Anyway import/exports and backups are two different tasks. If you have to backup a database, use its facilities. They usually allow far more control, i.e. point-in-time recovery. If you have to move data across databases that's another issue - I would write just the code to move data, not metadata, pre-creating the required structure in the target database.