For bank information you normally want to share the information. Putting information in a binary file is fine for local use, but not good for shared. Also, relational databases give you a lot of tools, which you will have to either live without or create on your own. There is really not much reason to not use a relational database in this case. The only thing I can come up with is that you have to keep the application very light. You have quite a few options for databases, and if you need growth, a database gives hou a lot of growth options. You can find out about the different editions of SQL Server here:
http://en.wikipedia.org/wiki/Microsoft_SQL_Server[
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