如何在JPA上连接键值表

@Entity
@Table(name = "key_value_table")
public class KeyValue {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "key_column")
    private String key;

    @Column(name = "value_column")
    private String value;

    // 省略构造函数、getter和setter方法
}

@Entity
@Table(name = "main_entity_table")
public class MainEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    // 其他属性...

    @OneToMany(mappedBy = "mainEntity", cascade = CascadeType.ALL)
    private List<KeyValue> keyValues;

    // 省略构造函数、getter和setter方法
}

// 插入数据
MainEntity mainEntity = new MainEntity();
KeyValue keyValue1 = new KeyValue("key1", "value1");
KeyValue keyValue2 = new KeyValue("key2", "value2");
mainEntity.setKeyValues(Arrays.asList(keyValue1, keyValue2));
entityManager.persist(mainEntity);

// 查询数据
MainEntity retrievedEntity = entityManager.find(MainEntity.class, mainEntity.getId());
List<KeyValue> keyValues = retrievedEntity.getKeyValues();

// 修改数据
keyValues.get(0).setValue("new value");
entityManager.merge(retrievedEntity);

// 删除数据
KeyValue keyValueToDelete = keyValues.get(1);
retrievedEntity.getKeyValues().remove(keyValueToDelete);
entityManager.remove(keyValueToDelete);