DDD-为什么实体的身份不仅仅是原始类型？

Question

将实体的ID定义为自定义类型而不是像数据库驱动的程序员通常那样定义为原始类型的目的是什么？

Answer 1

First of all, Domain entities must be designed independant from storage (other question is that sometimes it's impossible, but let's assume this). In real world (or in domain world) entites often has complex identity like first name, last name and password number. It's not a primitive. People don't have an int Id from thier birth, but they have names and other documents. So, you need to translate it to your domain model. Of couse, sometimes, you don't have such complex identity and you can replace it with some more simple, like int number. But in both cases your choice shouldn't be based on database if you try to use DDD (it's difficult, yes). And later, you create mapping from domain entities to tables or other storage.