Question

我有这两个表：

CREATE TABLE IF NOT EXISTS `functions` (
`idFunction` int(11) NOT NULL,
`idLanguage` int(11) NOT NULL,
`name` varchar(30) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`idCategory` int(11) DEFAULT '1',
PRIMARY KEY (`idFunction`,`idLanguage`),
KEY `idCategory` (`idCategory`),
KEY `idLanguage` (`idLanguage`),
CONSTRAINT `FK_functions_categories` FOREIGN KEY (`idCategory`) REFERENCES            
`category_package` (`idCategory`) ON DELETE NO ACTION ON UPDATE CASCADE,
CONSTRAINT `FK_functions_languages` FOREIGN KEY (`idLanguage`) REFERENCES `languages`  (`idLanguage`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `subfunctions` (
`idParent` int(11) NOT NULL,
`idChild` int(11) NOT NULL,
PRIMARY KEY (`idParent`,`idChild`),
KEY `idChild` (`idChild`),
CONSTRAINT `FK_subfunctions_functions` FOREIGN KEY (`idParent`) REFERENCES `functions` (`idFunction`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `FK_subfunctions_functions_2` FOREIGN KEY (`idChild`) REFERENCES `functions` (`idFunction`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

当我试图通过Hibernate的逆向工程映射这些表时，映射会发生，但是当我尝试执行涉及这两个表的查询时，Hibernate会抛出这个异常：

Foreign key (FKFD0F515B161D5928:subfunctions [idParent])) must have same number of columns as the referenced primary key (functions [idFunction,idLanguage])

我知道真正的交易是将idLanguage作为PK放在子功能表中，但我使用的是遗留数据库而我无法修改它。

有没有办法映射这个？

Answer 1

您没有提供有关映射的大量详细信息，因此在此处提供帮助并不容易。通常，因为两个表的主键都是复合键，所以可以将其映射到可嵌入类中，如http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#d0e2177中所示

上述类的示例映射可能类似于：

@Entity
@Table(name = "functions")
public class Functions {

    @Id
    private FunctionPK functionPK;

    @Column(name="name", nullable=false)
    private String name;

    @Column(name="idCategory", nullable=false)
    @ManyToOne(cascade=CascadeType.SAVE_UPDATE)
    @JoinColumn(name = "idCategory")
    private CategoryPackage idCategory;

...
}

@Embeddable 
  private class FunctionPK implements Serializable
  {

    @Column(name="idFunctions")
    private int idFunctions;

    @Column(name="idLanguage")
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name = "idLanguage")
    private Language idLanguage;

    //Some getters and setters 
    ...
  }

@Entity
@Table(name = "subfunctions")
public class SubFunctions {

    @Id
    private SubFunctionPK subFunctionPK;

...
}

@Embeddable 
  private class SubFunctionPK implements Serializable
  {

    @Column(name="idParent")
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name = "idFunction")
    private Functions idParent;

    @Column(name="idChild")
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name = "idFunction")
    private Functions idChild;

    //Some getters and setters 
    ...
  }

如何在Hibernate上映射这些表

1 个答案: