Hi, i am developing a system that must connect and retrieve data from several databases or files (SQLServer, Oracle, Access, Excel, XML files) to arrange information in a web page. The thing is that i donīt know exactly what DB to use at one point in time since it depends on user interaction.

I'm thinking...Strategy Design Pattern...And let the context decide what algorithm to use so another class can do the GUI presentation part

Is this a good choice???
or is there another pattern that is more suitable to take this task?