Sql server CE 4.0 in a Visual studio project suddenly losing data

Question

I am not sure if this is a setup issue from my side or some bug, but I am facing a really wierd problem.

I am developing against SQL Server CE 4.0 in a VS 2010 Winforms Project. It is kept in the project like so

Now what happens is, for some strange reason, whenever I encounter an exception in my application or do a schema update for database, I lose all my test data. Not just one table, all of it, entire database except for the schema objects.

Remember, I am not doing anything to regenerate the database from the model or anything. It just deletes all the data, and currently it is not even fully reproducible. Completely unpredictable. The schema remains intact even after the data is deleted.

Can any one help?

Answer 1

Okay I figured out the solution - very stupid of me, but I think others can make this same mistake so here goes -

I am using the connection string as |DataDirectory|\LocalDB.sdf and expected it to take it from the project directory - turns out it takes it from the debug folder instead. Makes sense now that I know it.

So whenever I do a schema update, the original database gets changed so it replaced the LocalDB present in the debug folder. Since the db in the project never had any data, I used to get the empty database unnecessarily.

Answer 2

Actually, after a change in the SQL Server CE database (in the schema, for example), it replaces the database inside the application with a new copy. If the database in sqlserver ce has a different set of data than the database inside the application, the previous data inside the application will be lost.