Hi,
it depends on what you want to do. If you want to consume data from a local database you should have a look at IndexedDB. For normal access to a database I would recommend that you build a service wrapper for the database and call this service in your app.
The same would I do for OData (except that you have to build a service).
Best Regards. When you see answers and helpful posts, please click Vote As Helpful, Propose As Answer, and/or Mark As Answer. This helps us build a healthy and positive community.