How to: Represent Columns as Allowing Null Values (LINQ to SQL)
Use the LINQ to SQL CanBeNull property on the ColumnAttribute attribute to specify that the associated database column can hold null values.
For code examples, see CanBeNull.
To designate a column as allowing null values
Add the CanBeNull property to the ColumnAttribute attribute.
Set the CanBeNull property value to true.
See Also
Concepts
Other Resources
How to: Customize Entity Classes by Using the Code Editor (LINQ to SQL)