Read original post at Kunal's Blog
Do you know that, Windows Phone 7.1 (Mango) now supports local database? Yes, you can now use local database inside your Phone 7 device and use it to CRUD operations. You can now create a DataContext class from an existing database and use it as the entry point class to do DB operation.
In this chapter we will learn how to create a DataContext class for local SQL CE database. At the end of this tutorial our data context class will be ready for further DB operations.