Hibernate 级联删除未按预期工作

Question

我正在使用 hibernate 3 并尝试删除数据库中的记录，但删除并未按我的预期进行。模式休眠正在工作（以伪代码）：

create table Employer(
    employer_id number(12) primary key,
    employer_name varchar2(50)
);

create table Employee(
    employee_id number(12) primary key,
    employee_name varchar2(50),
    employer_id number(12) foreign key references employer.employer_id not null
);

create table Employee_Roles(
    role_id number(12) primary key,
    employee_id number(12) foreign key references employee.employee_id not null,
    role varchar2(50)
);

我的休眠类映射看起来像：

@Entity
public class Employer{

    @Id
    @Column(name = "EMPLOYER_ID")
    private long id;

    @Column
    private String name;


    @OneToMany(targetEntity = Employee.class, fetch = FetchType.EAGER)
    @JoinColumn(name = "employer_id")
    @Cascade(CascadeType.ALL)
    private Set<Employee> employees;
}

@Entity
public class Employee{

    @ManyToOne(targetEntity = Employer.class)
    @JoinColumn(name = "employer_id")
    @Cascade(value = CascadeType.SAVE_UPDATE)
    private Employer employer;

    @OneToMany(targetEntity = EmployeeRole.class, fetch = FetchType.EAGER)
    @JoinColumn(name = "employee_id")
    @Cascade(CascadeType.ALL)
    private Set<Employee> employees;
}

@Entity
public class EmployeeRole{

    @ManyToOne(targetEntity = Employee.class)
    @JoinColumn(name = "employee_id")
    @Cascade(value = CascadeType.SAVE_UPDATE)
    private Employee employee;
}

现在使用此配置，我正在调用：

getCurrentSession().delete(someEmployerEntity);

发生的情况是：

Hibernate: update EMPLOYEE set EMPLOYEE_ID=null where EMPLOYEE_ID=?
Hibernate: update EMPLOYEE_ROLE set employee_id=null where employee_id==?
[2011-04-15 15:59:53,487] JDBCExceptionReporter WARN  - SQL Error: -10, SQLState: 23502
[2011-04-15 15:59:53,487] JDBCExceptionReporter ERROR - integrity constraint violation: NOT NULL check constraint; SYS_CT_10058 table: EMPLOYEE_ROLE

并引发异常。我期望 session.remove(..) 调用的结果是要删除的雇主记录，以及与雇主关联的所有雇员记录以及与已删除的雇员记录关联的所有 EmployeeRole 记录。这是一个正确的假设吗？或者我在这里误解了一个关键概念？

Answer 1

级联所有删除孤儿应该可以解决您的问题。然而，它是 Hibernate 的一部分，而不是 EJB 标准。如果您想这样做并且不想陷入供应商的解决方案中，我建议您查看 这篇文章。

祝你好运！

编辑：根据您的建议，我将“mappedBy”属性添加到 @OneToMany 注释中，这似乎是使用 inverse="true" 来指定拥有关系的注释方式。关系的相关更改部分如下所示：

public class Employee{

    @OneToMany(targetEntity = EmployeeRole.class, mappedBy="employee", fetch = FetchType.EAGER,  cascadeType=CascadeType.ALL)
    private Set<EmployeeRole> employeeRoles;
}


public class Employer{

    @OneToMany(targetEntity = Employee.class, mappedBy="employer", fetch = FetchType.EAGER, cascadeType=CascadeType.ALL)
    private Set<Employee> employees;
}