The column cannot contain null values. SqlCE exception

问题

I'm getting the following exception when I attempt to insert some sample data into a SQL Server CE 3.5 database inside a WP7 application:

Error: SqlCeException "The column cannot contain null values.
[ Column name = Name,Table name = Exam ]

The name is also the primary key. I think I have declared everything properly in the DataContext.

        private void InsertData()
        {
            mangoDb = new ExamDataContext();

            // create a new exam instance
            Exam exam = new Exam();
            exam.Name = "History";
            exam.Description ="History Exam";
            // add the new exam to the context
            mangoDb.Exams.InsertOnSubmit(exam);
            // save changes to the database
            mangoDb.SubmitChanges();
         }

Where have I gone wrong?

回答1:

I solved a problem like this modifying id field declaration by adding IDENTITY (1,1) so my id declaration becomes:

[id] int NOT NULL  IDENTITY (1,1)

回答2:

I solved the problem by deleting the index(es) of The Table. Not sure why it worked, but it certainly did, in case anyone else comes across this issue.

来源：https://stackoverflow.com/questions/12511549/the-column-cannot-contain-null-values-sqlce-exception