Issue with relative path to database saving data

Question

I am creating a bookingsystem but i ran in to a problem whith my database connections when i change from specific path to relative path for datasource, When i have a speciffic datasource it can update the database and add new items. But when i change to relative path, at runtime everything works just fine and everything but when i close the program everything that i have changed or added have been disposed and when i open it again nothing have been saved. This is how the relative path looks like

SqlConnection SQLCN = new SqlConnection
(@"Data Source=.\SQLEXPRESS;
AttachDbFilename=|DataDirectory|\Databas\TestDatabase.mdf;
Integrated Security=True;User Instance=True");

Any idea why it does like this?

Answer 1

That's because you override the database on each build.

Probably you have the Build Action set to Content and the Copy to Output Directory set to Copy If Newer.

From @steve's link, regarding the Copy if newer value:

We don’t recommend this option for .mdb or .mdf files. The database file can change even when no changes are made to the data. Simply opening a connection on a data file (for example, by expanding the Tables node in Server Explorer) can mark it as newer.