You cannot submit to a database unless you bind your form to the database by
using New from Data Connection when creating your form. If you don't do this,
you'll have to either write code or a web service to be able to submit data
to the database.

To submit a form to multiple sources, just create multiple submit data
connections and either use multiple "Submit using a data connection" rules on
a button, or in code behind a button.
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S.Y.M. Wong-A-Ton