/// <summary>
 /// Determines whether a default value definition is a null value.
 /// </summary>
 /// <param name="defaultValue">A column's default value.</param>
 /// <returns><c>true</c> if the provided default value is a null value; otherwise, <c>false</c>.</returns>
 protected static bool IsNullDefaultValue(string defaultValue)
 {
     return(!defaultValue.IsNullOrWhiteSpace() &&
            NullValues.Contains(defaultValue));
 }