What is the difference between null and System.DBNull.Value?

Question

Is there any difference between null and System.DBNull.Value? If yes, what is it?

I noticed this behavior now -

while (rdr.Read())
{
    if (rdr[\"I         


        

Answer 1

DataRow has a method that is called IsNull() that you can use to test the column if it has a null value - regarding to the null as it's seen by the database.

DataRow["col"]==null will allways be false.

use

DataRow r;
if (r.IsNull("col")) ...

instead.