java - hibernate中的单表策略继承

Question

我将使用三个简单的 Person 、 Teacher 和 Student 类在 hibernate 中进行简单继承。

这是我的父类(Person.java)

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "Person Type" , discriminatorType = DiscriminatorType.STRING)
@DiscriminatorValue(value = "Person")
public class Person implements Serializable {

    @Id
    @GeneratedValue
    private Integer id;
    private String name;
    private String address;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

我的Teacher.java类:

@Entity
@DiscriminatorValue(value = "Teacher")
public class Teacher extends Person implements Serializable {

    private String teacherDegree;

    public String getTeacherDegree() {
        return teacherDegree;
    }

    public void setTeacherDegree(String teacherDegree) {
        this.teacherDegree = teacherDegree;
    }
}

还有我的 Student.java 类:

@Entity
@DiscriminatorValue(value = "Student")
public class Student extends Person implements Serializable {

    private String studentCollege;

    public String getStudentCollege() {
        return studentCollege;
    }

    public void setStudentCollege(String studentCollege) {
        this.studentCollege = studentCollege;
    }
}

hibernate 配置:

...
        <property name="hibernate.hbm2ddl.auto">update</property>
        <property name="hibernate.current_session_context_class">thread</property>
        <mapping class="com.abc.Person"/>
        <mapping class="com.abc.Teacher"/>
        <mapping class="com.abc.Student"/>
...

测试人员类别:

    SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
    Session session = sessionFactory.openSession();
    session.beginTransaction();

    Teacher teacher2 = new Teacher();

    teacher2.setName("Teacher ABC"); // person property
    teacher2.setAddress("NewYork"); // person property
    teacher2.setTeacherDegree("phd"); // teacher property

    session.save(teacher2);

    session.getTransaction().commit();
    session.close();

但是我收到了这个错误:

ERROR: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Type) values ('NewYork', 'Teacher ABC', 'phd', 'Teacher')' at line 1

Answer 1

作为惯例，您应该采用以下样式。我现在不记得了，但我认为您需要对列名称中的空格进行某种转义。

@DiscriminatorColumn(name = "PERSON_TYPE" , discriminatorType = DiscriminatorType.STRING)

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