INSERT / UPDATE data using DBNull or null?

Question

When modifying data in a SQL Server database you can use either System.DBNull.Value or null to represent a NULL value. Both of these will work and will set the proper value to NULL.

My question is - which of these is preferred, and why? Are there certain cases where one should be used in place of the other?

Answer 1

From System.DBNull.Value != null, and by testing this code:

var result = (System.DBNull.Value == null); // this is always false

We can see that the CLR doesn't treat them the same way. When retrieving data from a database we need to check for DBNull.Value and not a null reference.

Although it doesn't matter which we use to INSERT or UPDATE data, I would tend to stick with DBNull.Value for consistency through data access code.

There are a variety of other opinions in the question C# Database Access: DBNull vs null