DBNull

noun

say it: “DEE-bee nul” /ˈdiːbiː nʌl/

The value ADO.NET uses for a database NULL, which is not the same as C#'s null.

What is DBNull in C#?

DBNull — The value ADO.NET hands you for a database NULL, as DBNull.Value. It isn't C#'s null, so check for it with reader.IsDBNull(...) before you read the column.

int column = reader.GetOrdinal("Region");
string? region = reader.IsDBNull(column) ? null : reader.GetString(column);

In a sentence

• “Reading the Region column threw an error until I checked for DBNull first.”

Level: Journeyman · More C# terms at this level

Updated October 28, 2026