Hibernate映射异常与连接表

Question

我一直在面对映射异常，我简直不明白。 这里是个例外：

Caused by: org.hibernate.MappingException: Foreign key (FKCA2E919A5E0752D:cim10_indicationgroup_indicator [indicatorId])) must have same number of columns as the referenced primary key (cim10_indicationgroup [indicationGroupId,cim10Id]) 

的表如下（通知已经是关于PK差异）：

desc cim10_indicationgroup_indicator; 
+-------------------------+---------+------+-----+---------+-------+ 
| Field     | Type | Null | Key | Default | Extra | 
+-------------------------+---------+------+-----+---------+-------+ 
| cim10_indicationgroupId | int(11) | NO | PRI | NULL |  | 
| indicatorId    | int(11) | NO | PRI | NULL |  | 
+-------------------------+---------+------+-----+---------+-------+ 

desc cim10_indicationgroup; 
+-------------------------+---------+------+-----+---------+-------+ 
| Field     | Type | Null | Key | Default | Extra | 
+-------------------------+---------+------+-----+---------+-------+ 
| cim10_indicationGroupId | int(11) | NO | PRI | NULL |  | 
| indicationGroupId  | int(11) | NO | MUL | NULL |  | 
| cim10Id     | int(11) | NO | MUL | NULL |  | 
+-------------------------+---------+------+-----+---------+-------+ 

desc indicator; 
+-------------+--------------+------+-----+---------+-------+ 
| Field  | Type   | Null | Key | Default | Extra | 
+-------------+--------------+------+-----+---------+-------+ 
| indicatorId | int(11)  | NO | PRI | NULL |  | 
| indicator | varchar(255) | NO |  | NULL |  | 
+-------------+--------------+------+-----+---------+-------+ 

在休眠方面，实体立场如下：

@Entity 
@Table(name = "cim10_indicationgroup") 
@Immutable 
public class Cim10IndicationGroupCouple { 

    @Id 
    @Column(name = "cim10_indicationGroupId") 
    private Integer cim10IndicationGroupId; 

    @Column(name = "indicationGroupId") 
    private Integer indicationGroupId; 

    @Column(name = "cim10Id") 
    private Integer cim10Id; 

    @ManyToMany 
    @JoinTable(
     name = "cim10_indicationgroup_indicator", 
     joinColumns = @JoinColumn(name = "indicatorId") 
    ) 
    private Set<Indicator> indicators; 

    // getters, setters, equals/hashcode 

并参考实体：

@Entity 
@Table(name = "indicator") 
@Immutable 
public class Indicator { 

    @Id 
    @Column(name = "indicatorId") 
    private Integer id; 

    @Column(name = "indicator") 
    private String indicator; 

    // getters, setters, equals/hashcode 

作为奖励，来这里的元数据，从加入问题表：

SHOW KEYS FROM cim10_indicationgroup\G 
*************************** 1. row *************************** 
     Table: cim10_indicationgroup 
    Non_unique: 0 
    Key_name: PRIMARY 
Seq_in_index: 1 
Column_name: cim10_indicationGroupId 
    Collation: A 
Cardinality: 10137 
    Sub_part: NULL 
     Packed: NULL 
     Null: 
    Index_type: BTREE 
    Comment: 
*************************** 2. row *************************** 
     Table: cim10_indicationgroup 
    Non_unique: 0 
    Key_name: cim10_indicationGroup_pk 
Seq_in_index: 1 
Column_name: cim10Id 
    Collation: A 
Cardinality: 10137 
    Sub_part: NULL 
     Packed: NULL 
     Null: 
    Index_type: BTREE 
    Comment: 
*************************** 3. row *************************** 
     Table: cim10_indicationgroup 
    Non_unique: 0 
    Key_name: cim10_indicationGroup_pk 
Seq_in_index: 2 
Column_name: indicationGroupId 
    Collation: A 
Cardinality: 10137 
    Sub_part: NULL 
     Packed: NULL 
     Null: 
    Index_type: BTREE 
    Comment: 
*************************** 4. row *************************** 
     Table: cim10_indicationgroup 
    Non_unique: 1 
    Key_name: fk_cim10_indicationGroup_indicationGroup 
Seq_in_index: 1 
Column_name: indicationGroupId 
    Collation: A 
Cardinality: 633 
    Sub_part: NULL 
     Packed: NULL 
     Null: 
    Index_type: BTREE 
    Comment: 

为什么有映射例外呢？

Answer 1

我认为你的@ManyToMany映射是错误的。 joinColumn指定用于连接源实体（'Cim10IndicationGroupCouple'）和连接表的列，inverseJoinColumn指定用于连接目标实体（'Indicator'）的列。试试这个

@ManyToMany 
@JoinTable(
    name = "cim10_indicationgroup_indicator", 
    joinColumns = {@JoinColumn(name = "cim10_indicationgroupId")}, 
    inverseJoinColumns={@JoinColumn(name="indicatorId")} 
) 
private Set<Indicator> indicators; 

我同意这个例外是有误导性的，特别是如果这个修复了它的话。