Hibernate 多個@ManyToMany 關聯到同一個實體

Question

我有以下情況：

我有一個名為MyOtherEntity的實體，它有一個 type 屬性。 MyEntity僅與基於MyOtherEntity類型的某些MyOtherEntity實體相關聯。

MyEntity class（僅用於演示，未正確建模）：

@Data
@Entity
@Table(name = "my_table")
public class MyEntity {

    @ManyToMany(fetch = FetchType.LAZY)
    @JoinTable(
        name = "my_entity_my_other_entity_type1",
        joinColumns = {@JoinColumn(name = "my_entity_id")},
        inverseJoinColumns = {@JoinColumn(name = "my_other_entity_id")}
    )
    private List<MyOtherEntity> myOtherEntityType1;

    @ManyToMany(fetch = FetchType.LAZY)
    @JoinTable(
        name = "my_entity_my_other_entity_type2",
        joinColumns = {@JoinColumn(name = "my_entity_id")},
        inverseJoinColumns = {@JoinColumn(name = "my_other_entity_id")}
    )
    private List<MyOtherEntity> myOtherEntityType2;

    // more fields
}

MyOtherEntity class：

@Data
@Entity
@Table(name = "my_other_entity")
public class MyOtherEntity {

    private String type;

    // more fields
}

一個更詳細的例子：

假設只有 3 種類型的MyOtherEntity ，type1、type2 和 type3。 我的目標是僅MyEntity與 type1 和 type2 的MyOtherEntity實體相關聯。

使用 Hibernate 是否可以實現此功能？

Answer 1

您可以使用@Where 注釋。

@Where(clause = "type = 'tyep1'")
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(
    name = "my_entity_my_other_entity_type1",
    joinColumns = {@JoinColumn(name = "my_entity_id")},
    inverseJoinColumns = {@JoinColumn(name = "my_other_entity_id")}
)
private List<MyOtherEntity> myOtherEntityType1;

@Where(clause = "type = 'tyep2'")
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(
    name = "my_entity_my_other_entity_type2",
    joinColumns = {@JoinColumn(name = "my_entity_id")},
    inverseJoinColumns = {@JoinColumn(name = "my_other_entity_id")}
)
private List<MyOtherEntity> myOtherEntityType2;