Question

I am retrieving columns of different types and checking for null before assigning the class’s corresponding property. For string column Its all good. However, I need to decide what to do for the DateTime, Bool and the Enum type?

a) Do I should use nullable DateTime property for Class A or there is a better practice?

b) Is the checking for enum and the bool correct in the below code or there is a better way fo doing this?

 public static List<ClassA> Select(string connectionString)
        {
            List<ClassA> ClassAList = new List<ClassA>();
            using (SqlConnection con = new SqlConnection(connectionString))
            {
                con.Open();
                using (SqlCommand command = new SqlCommand(SPROC_ClassA_Select, con))
                {

                    using (SqlDataReader reader = command.ExecuteReader())
                    {
                        int MyGuidOrdinal   = reader.GetOrdinal("MyGuid") ;
                        int MyStringOrdinal = reader.GetOrdinal("MyString") ;
                        int MyDateTimeOrdinal = reader.GetOrdinal("MyDateTime") ;
                        int MyBooleanOrdinal    = reader.GetOrdinal("MyBoolean") ;
                        int MyEnumValueOrdinal  = reader.GetOrdinal("MyEnumValue") ;

                        if(reader.HasRows)
                        {
                            while (reader.Read())
                            {
                                ClassA classA = new ClassA
                                {
                                    MyGuid = reader.GetGuid(MyGuidOrdinal),
                                    MyString = reader["MyString"] is DBNull ? null : reader.GetString(MyStringOrdinal),
                                    MyDateTime = reader["MyDateTime"] is DBNull ? DateTime.MinValue : reader.GetDateTime(MyDateTimeOrdinal),                         
                                    MyBoolean = reader["MyBoolean"] is DBNull ? false : reader.GetBoolean(MyBooleanOrdinal),          
                                    MyEnumValue = reader["MyEnumValue"] is DBNull ? (int)MyEnumValue.Value1 : reader.GetInt32(MyEnumValueOrdinal),

                                };

                                ClassAList.Add(classA);
                            }
                        }
                        return ClassAList;

                    }


                }
            }

And below is the enum:-

public enum MyEnumValue 
{
 value1 =1,
 value2
}

Answer 1

If you want your class to be able to properly maintain database values without loss, you should use nullable types for boolean, date, and probably enum values. Otherwise, if you send your data back to the database, you could be changing all null values to default values when you update data.

Also, wouldn’t the code be a bit better if you used something like reader.IsDBNull() to check for null values?