Handling Null Values

nvenkat75 · March 28th, 2005, 05:17 AM

Hi,

How to get rid of these null value exceptions.

CODE Sample

strSQL= "select * from department where departmentid = 'D101';
cmd = new SqlCommand(strSQL,conn);

reader = cmd.ExecuteReader();

while(reader.Read())
{
m_Deptname = reader.GetString(1);
m_Description=reader.GetString(2);
}

Table
departmentid varchar(15)
departmentname varchar(30)
description varchar(50)

Sample Data

ID Name Description

D101 Accounts Accounts Dept
D102 Admin Admin Dept
D103 HRM <NULL>
D104 IT <NULL>
D105 Prod Production Dept

if the column description has a null value(Ex: D103,D104) is accessed, i get the error as mentioned below. but its working fine for the other sample criteria

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlTypes.SqlNullValueException: Data is Null. This method or property cannot be called on Null values.

thanks,

Venkat

Strength is Life, Weakness is Death

- Swami Vivekananda

mehdi62b · March 28th, 2005, 11:14 AM

Code:

while(reader.Read())
{
if(!reader.IsDBNull(1)) 
    m_Deptname = reader.GetString(1);
//else{for null values}
if(!reader.IsDBNull(2)) 
    m_Description=reader.GetString(2);
//else{for null values}
}

_____________
Mehdi.
software student.

helenas · January 16th, 2006, 05:46 PM

Hi

What may be the reason for "No data exists for the row/column" error
when using reader.IsDBNull(0) method? I catch such error!!

FYI: reader contains data (reader.HasRows is true) and field with index 0 IS NOT NULL!!!

Helena