After around 23 minutes Dean discusses DDD and describes an Entity as being stateless. I am sorry to disagree. An Entity by definition has state and an identity. If modeled correctly the identity of an Entity has to be unique, which means there is only one instance of an Entity with a certain identity in the whole system. It also can be queried by identity. In contrast Value Objects do not have an identity and therefore can not be queried. They are not unique. Often (complex) Value Objects one way or another belong to a certain instance of an Entity meaning that without the Entity it would not make sense to create or have the Value Object. On the other hand it is not uncommon to model Domain Events as Value Objects. Value Objects are also useful for context mapping. Nevertheless this is one of the most brilliant talks I have seen in recent years. Thanks Dean.
After around 23 minutes Dean discusses DDD and describes an Entity as being stateless. I am sorry to disagree. An Entity by definition has state and an identity. If modeled correctly the identity of an Entity has to be unique, which means there is only one instance of an Entity with a certain identity in the whole system. It also can be queried by identity. In contrast Value Objects do not have an identity and therefore can not be queried. They are not unique. Often (complex) Value Objects one way or another belong to a certain instance of an Entity meaning that without the Entity it would not make sense to create or have the Value Object. On the other hand it is not uncommon to model Domain Events as Value Objects. Value Objects are also useful for context mapping. Nevertheless this is one of the most brilliant talks I have seen in recent years. Thanks Dean.