Hi,
primitive types can't be null. but to reduce the impedance missmatch between database and programing languages like C# MS has come up with the nullable types.
Thanks,
Chinna
Nullable types represent value-type variables that can be assigned the value of null.
The syntax T? is shorthand for System.Nullable<T>, where T is a value type. The two forms are interchangeable.
Assign a value to a nullable type in the same way as for an ordinary value type,
for example int? x = 10; or double? d = 4.108;
Use the System.Nullable.GetValueOrDefault property to return either the assigned value, or the default value for the underlying type if the value is null, for example int j = x.GetValueOrDefault();
For more information visit this link:
http://msdn.microsoft.com/en-us/library/1t3y8s4s(VS.80).aspx