error nullable type although specified ? in prop

Question

hello. so Im trying to get a query select statement from db, read it and attach it to an object , like so:

 using (OracleDataReader reader = cmd.ExecuteReader())  
                    {  
                        //for every row  
                        while (reader.Read())  
                        {  
                            //creating an instance of record class and filling with column's values  
                            RecordObject item = new RecordObject  
                            {  
                                Id = reader.GetInt32(0),  
                                System_Id = reader.GetString(1),  
                                System_Name = reader.GetString(2),  
                                Company_Id = reader.GetInt32(3),  
                                Company_Name = reader.GetString(4),  
                                Interface = reader.GetInt32(5),  
                                Service_Id = reader.GetInt32(6),  
                                Order_Company_Id = reader.GetString(7),  
                                Time_Stamp = reader.GetString(8),  
                                Zehut = reader.GetString(9),  
                                First_Name = reader.GetString(10),  
                                Last_Name = reader.GetString(11),  
                                Tik_Date = (string?)reader.GetString(12),  

                            };  
                            //adding object to list  
                            list.Add(item);  
                        }  
}  

everything works fine except to TIK_DATE(Last property) given error: 'Column contains NULL data'
in my class, I define it the property like: public string? Tik_Date{ get; set; }
what could be the problem??

edit
i added the following extension to support nulls of strings:

public static string SafeGetString(this OracleDataReader reader, int colIndex)  
        {  
            if (!reader.IsDBNull(colIndex))  
                return reader.GetString(colIndex);  
            return string.Empty;  
        }   

but dont know how to do the same with integer, any ideas?

Answer 1

Hi @gal mor , Welcome to Q&A.

For checking null values you should use a ternary method similar to the following.

int columnValue = reader.IsDBNull(0) ? 0 : reader.GetInt32(0);  

For the code you write:

 public static string SafeGetString(this OracleDataReader reader, int colIndex)  
         {  
             if (!reader.IsDBNull(colIndex))  
                 return reader.GetString(colIndex);  
             return string.Empty;  
         }   

You could call it like this.

string columnValue = reader.SafeGetInt32(0);  

Best Regards,
Jiale

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