The purpose of nullable type is to read data from the database and it may be empty, rather than inserting it. All data must be inserted to verify. If you want to insert null in the database, you can use it.
Determine whether the retrieved data is null in the database. If so, assign it to the nullable datetime Lockdatatime attribute.
= (5) ? null : (DateTime?)(5);
Determine whether the retrieved data is null in the database. If so, assign it to the nullable int Testint property.
= (6) ? null : (int?)reader.GetInt32(6);