I do not know whether parallelizing processes will make your loading significantly faster, but if it really takes days to load the data into your database, you may want to think about some other ways of doing the work.

You did not specify on which database engine you are working, so it is difficult to give specific advice, but you may think about a few things that may help getting better performance:

• Using SQL Loader (for Oracle, or similar tools)
• Better management of transactions;
• Modifying the commit rate if applicable;
• De-activating the redo logs, the statistics, etc.;
• Dropping the indexes prior to loading the data and rebuilding them only at the end.