How can I check for DBNull while executing my command only once?

Question

When I retrieve any Scalar value from the database, I usually write code like this for nullable fields.

cmd.ExecuteScalar() == DBNull.Value ? 0 : (int)cmd.ExecuteScalar()

But I don't like it because it executes the Executescalar statement twice. It's an extra trip to the server for my website and in favor of performance I don't want to do this.

Is there any way I can get rid of this extra ExecuteScalar()?

Answer 1

Just use a variable to cache the result:

var o = cmd.ExecuteScalar();
return o == DBNull.Value ? 0 : (int)o;

Answer 2

 object o = cmd.ExecuteScalar();
 return (o== DBNull.Value) ? 0 : (int)o;

Answer 3

Write yourself an extension method for the sql command.

public static T ExecuteNullableScalar<T>(this SqlCommand cmd)
    where T : struct
{
    var result = cmd.ExecuteScalar();
    if (result == DBNull.Value) return default(T);
    return (T)result;
}

Usage becomes:

int value = cmd.ExecuteNullableScalar<int>();