Jpa Hibernate映射键多列关系

我想映射一个Java映射表，其中所有键值存储在同一个表中。与https://en.wikibooks.org/wiki/Java_Persistence/Relationships#Example_of_a_map_key_column_relationship_database 类似的东西，但关键是一个对象，而不是一个简单的类型。Jpa Hibernate映射键多列关系

说我有一个实体的 “用户”

@Entity 
public class User{ 
    @Id 
    private String userId; 

    @OneToMany 
    @MapKeyClass(CalenderWeek.class) 
    private Map<CalenderWeek, WorkedTime> workedTimeMap;

关键CalendarWeek会是这样的

@Embeddable 
public class CalenderWeek { 
    int year; 
    Month month; // Month is the enum java.time.Month

的WorkedTime会是这样的

@Embeddable 
public class WorkedTime { 
    private long workedHours;

相应的工作时间表应该是这样的

worked_time 

user_id | year | month | worked_hours 
---------|------|-------| --- 
1  | 2017 | 11 | 42

是否有可能拿到或做我必须做如下描述 https://en.wikibooks.org/wiki/Java_Persistence/Relationships#Example_of_a_map_key_class_embedded_relationship_annotation

即，三个用表。

来源

2017-03-08 fan

一般来说，如果你想有一个地图ü只需使用@ElementCollection注释，如果你想覆盖一些列或协会从Embeddables然后使用@AttributeOverride/@AssociationOverride的：

@ElementCollection 
@AttributeOverrides({ 
@AttributeOverride(name="key.year", 
[email protected](name="YEAR1")), 
@AttributeOverride(name="value.workedHours", 
[email protected](name="WORKED_H")) 
}) 
private Map<CalenderWeek, WorkedTime> workedTimeMap;

根据无论是要覆盖键还是值属性，都要分别为持久性提供程序添加这些前缀，以便能够重新识别差异。

来源

2017-03-08 13:57:52

只是为了让它完成@CollectionTable（名= “worked_time”， joinColumns = @ JoinColumn（名=“user_id”））也是需要的。 – fan

我假设你想每个月+年存储一个用户的工作时间。看看你的结果表，我会建议不要使用Embeddable。你可以试试这个方法：

@Entity 
public class User{ 

    @Id 
    private String id;  

    @OneToMany(mappedBy = "user", fetch = FetchType.LAZY) 
    private List<WorkedTime> workedTime;

加回参考：

@Entity 
public class WorkedTime { 

    @Id 
    private long id; 

    @ManyToOne 
    @JoinColumn(name = "user_id", nullable = false) 
    private User user; 

    private int year; 

    private Month month; 

    private long workedHours;

这将导致只有两个表。

来源

2017-03-08 13:52:59 KLHauser

Maciej Kowalski的答案非常有用和正确。谢谢。

我只想在这里完成答案，并稍微扩展它，因为我在最后使用了xml配置。的注释版本结束这样的

@Entity 
public class UserWorklogAggregate { 
@Id 
private String userId; 

@ElementCollection 
@CollectionTable(
     name = "worked_time", 
     joinColumns = @JoinColumn(name = "user_id") 
) 
@AttributeOverrides({ 
     @AttributeOverride(name = "key.year", column = @Column(name = "year")), 
     @AttributeOverride(name = "key.week", column = @Column(name = "week")), 
     @AttributeOverride(name = "value.workedDuration", column = @Column(name = "worked_duration")) 
}) 
private final Map<CalenderWeek, WorkedTime> workedTimeMap = new HashMap<>();

和XML版本

<?xml version="1.0"?> 
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> 
<hibernate-mapping default-access="field" default-cascade="all"> 

<class name="org.whatever.UserWorklogAggregate" table="user_worklog_aggregate"> 
    <id name="userId" length="10" column="user_id" /> 
    <map name="workedTimeMap" table="worked_time" > 
     <key column="user_id" /> 
     <composite-map-key class="org.whatever.CalenderWeek"> 
      <key-property name="year" column="year"/> 
      <key-property name="week" column="week"/> 
     </composite-map-key> 
     <composite-element class="org.whatever.WorkedTime" > 
      <property name="workedDuration" column="worked_duration"/> 
     </composite-element> 
    </map> 
</class>

来源

2017-03-15 13:44:17 fan

Jpa Hibernate映射键多列关系

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