save and retrive data from local database

Question

Hai,

         I have a problem in saving data in my database.

The system I am developing saves data in the database and displays the data in the datagrid and that runs smoothly, but the problem is whenever I restart or reboot the application the data disappears and the database was again empty.I refer in many website and got answer to change properties of local database copy to output directory to copy if newer. I modify this property in my local database but still i am facing the same propblem.... How can i use this.

 And also  I have  one doubt.I am doing the hole project using local database(.sdf). If it is safe to use or not.

Please help me......

 Very immediate please....

 Thanks to everyone......