Question

我一直面临着一个我不理解的映射异常。这是一个例外：

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])

表格如下（已经注意到PK的差异）：

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

引用的实体：

@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，这里有来自有问题的联接表的元数据：

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:

为什么会出现映射异常？

Answer 1

我认为你的@ManyToMany映射是错误的。 joinColumn指定用于将源实体（'Cim10IndicationGroupCouple'）与连接表连接的列，inverseJoinColumn指定用于连接目标实体的列（'Indicator'）。试试这个

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

我同意该异常具有误导性，特别是如果这样做会解决它。

带连接表的Hibernate映射异常

1 个答案: