How To Edit .sdf file

Question

I have my application and I install a .sdf file and I add columns to my database. So how do I update my database without losing my Data?

Answer 1

You can extend/update a database schema by choosing Default Values for new columns or allow new columns to accept Nulls.

Answer 2

You can execute standard data definition language (DDL) commands in code at application startup.

For example:

myCommand.ExecuteNonQuery("ALTER TABLE MyTable ADD NewColumn1 INT NULL")

We have done this for years in devices ranging from PocketPC to Tablets.

We used to check whether or not a database table or column existed before modifying the DB structure, but we have found it is much easier to record the current database version in a table and then just check the version on startup then make the modifications that we know are necessary between the current version in the database and the application's database version.