Java/Hibernate JPA : InheritanceType. TABLE_PER_CLASS 和 ID

Question

我正在使用 Hibernate JPA。

假设我有这些类:

AbstractPerson
|--> ConcreteEmployee
|--> ConcreteCustomer

有没有办法让具体的类有独立的ID？

我正在使用 InheritanceType.TABLE_PER_CLASS。

Answer 1

来自 Hibernate 注释引用指南:

2.2.4.1. Table per class

This strategy has many drawbacks (esp. with polymorphic queries and associations) explained in the JPA spec, the Hibernate reference documentation, Hibernate in Action, and many other places. Hibernate work around most of them implementing this strategy using SQL UNION queries. It is commonly used for the top level of an inheritance hierarchy:

@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Flight implements Serializable { ... } 

This strategy supports one-to-many associations provided that they are bidirectional. This strategy does not support the IDENTITY generator strategy: the id has to be shared across several tables. Consequently, when using this strategy, you should not use AUTO nor IDENTITY.

所以恐怕你想要的不被支持(我建议使用GenerationType.TABLE)。