JPA + Hibernate映射为扩展表

对于在我们的项目的要求之一，我们以下几点：JPA + Hibernate映射为扩展表

http://msdn.microsoft.com/en-us/library/aa479086.aspx#mlttntda_nvp来管理多个租户。

请参考上面的表格结构图的链接。

我需要帮助来管理映射。这是我在想什么：

@Entity 
    @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) 
    public abstract class AbstractEntity { 
    @Id @GeneratedValue(strategy = GenerationType.TABLE) 
    private Long id; 

    @OneToMany(mappedBy="entities") 
    private Set<ExtensionTable> extensionTable = new HashSet<ExtensionTable>(); 

    .... 
} 


@Entity 
public class ExtensionTable { 
    @Id @GeneratedValue 
    private Long id; 

    @ManyToOne 
    private Set<AbstractEntity> entities = new HashSet<AbstractEntity>(); 

    ... 
} 

@Entity 
public class Employee extends AbstractEntity { 
    ... 
}

我发现很难定义元数据表的映射。

来源

2013-03-18 bornleo

从规范11.1.26：ManyToOne注释定义了一个单值关联到另一个具有多对一多重性的实体类。我不认为你可以在Set中使用@ManyToOne。我会尝试这样的：

@Entity 
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) // Depending on your provider, I generally use JOINED or SINGLE_TABLE 
public abstract class AbstractEntity { 
    @Id @GeneratedValue(strategy = GenerationType.TABLE) 
    private Long id; 

    @OneToMany(mappedBy="entity") 
    private Set<ExtensionTable> extensionTable = new HashSet<ExtensionTable>(); 

    .... 
} 


@Entity 
public class ExtensionTable { 
    @Id @GeneratedValue 
    private Long id; 

    @ManyToOne 
    private AbstractEntity entity; 

    @ManyToOne 
    private Metadata metadata;  

    @Column 
    private String value; 

    ... 
} 

@Entity 
public class Metadata { 
    @Id @GeneratedValue 
    private Long id; 

    @ManyToOne 
    private AbstractEntity entity; 

    @Column 
    private String extLabel;   

    @Column 
    private String extDataType; // So, here is a problem, you'll have to find an efficient way to deal with the data type. 
    ... 
} 

@Entity 
public class Employee extends AbstractEntity { 
    ... 
}

来源

2013-03-19 16:03:47 Eus777

我的不好，我没有想到它通过。以下是最终代码：

@Entity 
    @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) 
    public abstract class AbstractEntity { 

@Id 
@GeneratedValue(strategy = GenerationType.AUTO) 
private Long id; 

@Column(name="TENANT_ID") 
private int tenantId; 

@OneToMany(mappedBy="entity",cascade=CascadeType.ALL,fetch = FetchType.EAGER) 
private Set<ExtensionTable> extensionTable = new HashSet<ExtensionTable>(); 

..... 
} 


@Entity 
@Table (name="metadata") 
public class MetaData { 

@Id 
@GeneratedValue(strategy = GenerationType.AUTO) 
private Long metaDataId; 

@Column 
int tenantId; 

@ManyToOne(cascade=CascadeType.ALL) 
@JoinColumn(name="extensionId") 
    private ExtensionTable extension; 

@Column 
String extLabel; 

@Column 
String extDataType; 

    ..... 

    } 

@Entity 
@Table(name = "extensionTable") 
public class ExtensionTable { 
@Id 
@GeneratedValue(strategy = GenerationType.AUTO) 
private Long extensionId; 

@ManyToOne(cascade=CascadeType.ALL) 
@JoinColumn(name="ENTITY_ID") 
    private AbstractEntity entity; 

@OneToOne(cascade=CascadeType.ALL,fetch = FetchType.EAGER) 
@JoinColumn(name="metadata_id") 
private MetaData metaDatas = new MetaData(); 

    .... 

    }

来源

2013-03-19 23:48:46 bornleo

JPA + Hibernate映射为扩展表

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