Question

我有以下两个类（及其pk类）和这些注释。我删除了setter / getters / hashcode / equals以压缩示例

我最终收到此错误

org.hibernate.MappingException: Repeated column in mapping for collection: com.stackOverflow.Features.thingCategory column: YEAR

我的猜测是因为“年”在连接表中共享，我搞砸了一些用于关联我的实体的语法。请注意，这些视图在其实体之间具有隐式关系，我试图在我的注释中建模。我尝试了一些JPA建模工具，它们在建模后给出了相同的错误。我已尝试将连接列设置为insertable，updatable设置为false。

我当然可以写一个SQL查询，但我真的很惊讶Hibernate在我看来有多难。

功能实体

@Entity
@Table(name = "myTableOfFeatures")
public class Feature {
    private static final long serialVersionUID = 1L;

    @EmbeddedId
    private FeatureKey id;

    @Column(name="displayText")
    private String description;

    //bi-directional many-to-many association
    @ManyToMany
    @JoinTable(
            name="joinTableToThingCategories"
            , joinColumns={
            @JoinColumn(name="name", referencedColumnName="name", insertable = false, updatable = false),
            @JoinColumn(name="year", referencedColumnName="year", insertable = false, updatable = false)
    }
            , inverseJoinColumns={
            @JoinColumn(name="year", referencedColumnName="year", insertable = false, updatable = false),
            @JoinColumn(name="title", referencedColumnName="title", insertable = false, updatable = false)
    }
    )
    private List<ThingCategory> thingCategory;

    public Feature() {
    } 
    // ... gets and sets

} 
@Embeddable
public class FeatureKey implements Serializable {
    //default serial version id, required for serializable classes.
    private static final long serialVersionUID = 1L;

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

    private String year;

    public FeatureKey() {
    }
    // ... gets and sets and equals and hashes
}

ThingCategory实体

@Entity
@Table(name = "CategoriesOfThings")
public class ThingCategory implements Serializable {
    private static final long serialVersionUID = 1L;

    @EmbeddedId
    private ThingCategoryKey id;

    private String comment;

    //bi-directional many-to-many association to categories
    @ManyToMany(mappedBy="thingCategory")
    private List<Feature> features;

    public ThingCategory() {
    }
    // ... gets and sets
}
@Embeddable
public class ThingCategoryKey implements Serializable {
    //default serial version id, required for serializable classes.
    private static final long serialVersionUID = 1L;

    private String year;

    @Column(name="categoryName")
    private String title;

    public ThingCategoryKey() {
    }
    // ... gets and sets and equals and hashes
}

Answer 1

这是JPA 2.1规范中的一个例子。我希望它有所帮助。

@Entity
public class Employee {
    @Id int id;
    @Embedded ContactInfo contactInfo;
    ...
}


@Embeddable
public class ContactInfo {
    @ManyToOne Address address; // Unidirectional
    @ManyToMany List<PhoneNumber> phoneNumbers; // Bidirectional 
}

@Entity
public class PhoneNumber {
    @Id int phNumber; 

    @ManyToMany(mappedBy="contactInfo.phoneNumbers")         
    Collection<Employee> employees;
}

我强烈推荐你这个规格。 JPA 2.1

Answer 2

这可能有用，但我没有尝试过;所以我想把它写成评论，但把代码写成评论很麻烦。所以你可能想尝试它，如果它工作（抱歉没有时间尝试）。如果它不起作用，请给我留言，我会删除它。

@JoinTable(
        name="joinTableToThingCategories", 
        joinColumns={
            @JoinColumn(name="feature_name", referencedColumnName="name", insertable = false, updatable = false),
            @JoinColumn(name="feature_year", referencedColumnName="year", insertable = false, updatable = false)
        }, 
        inverseJoinColumns={
            @JoinColumn(name="tcat_year", referencedColumnName="year", insertable = false, updatable = false),
            @JoinColumn(name="tcat_title", referencedColumnName="title", insertable = false, updatable = false)
       }
)
private List<ThingCategory> thingCategory;

多对多JPA Hibernate通过连接表错误映射组合键

2 个答案: