android.database.sqlite。SQLiteException:没有这样的列:due_date(代码1):

I am using eclipse to do an android development. In my app, i will have a query to get the assignment which is stored in the database. I want it to be ordered by the due date but I encountered this problem when I tried to run my app on the emulator and the emulator shows an error like this: I am using eclipse to do an android development