title: Is every property of an Entity in domain driven design a value object?
body: <p>I'm reading "Patterns, Principles, and Practices of Domain-Driven Design". The book suggests that properties of an <code>Entity</code> should be value objects in order to model domain's ubiquities language. I've seen many examples like <code>EmailAddress</code> or <code>Age</code> with only one field to model domain concepts. I'm confused about it. Is every property of an <code>Entity</code> a value object? Can you provide examples when we can use normal languages provided data types for properties?</p>