Override inherited properties (such as inherited relationships table name, columns names…etc) of a @MappedSuperclass in the subclass entity

huangapple
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英文:

Override inherited properties (such as inherited relationships table name, columns names...etc) of a @MappedSuperclass in the subclass entity

问题

这是我的抽象父类：

  1. @MappedSuperclass
  2. public class AbstractEntity {
  4.   @ManyToMany
  5.   protected Set<UserGroupAccess> userGroupAccesses = new HashSet<>();
  7.   @ManyToMany
  8.   protected Set<UserAccess> userAccesses = new HashSet<>();
  10. }

以下是继承上述 AbstractEntity 的两个实体：

  1. @Entity
  2. public class Project extends AbstractEntity {
  3.     // 其他属性
  4. }
  6. @Entity
  7. public class TodoTask extends AbstractEntity {
  8.     // 其他属性
  9. }

我希望在每个子类实体中覆盖并拥有由 userGroupAccesses 和 userAccesses 表示的关系的表。举例来说，对于 Project 实体，我希望它有自己的表 projectuserGroupAccesses 和一个表 projectuserAccesses，来表示在 AbstractEntity 超类中定义的关系。

以前，我可以通过实体的 XML 表示来解决这种问题，我只需要在每个实体的 XML 中定义以下内容：

  1. <set name="userGroupAccesses" table="projectusergroupaccesses" cascade="all-delete-orphan">
  2.       <cache usage="read-write" />
  3.       <key column="projectid" />
  4.       <many-to-many class="org.hisp.dhis.user.UserGroupAccess" column="usergroupaccessid" unique="true" />
  5. </set>
  7. <set name="userAccesses" table="projectuseraccesses" cascade="all-delete-orphan">
  8.       <cache usage="read-write" />
  9.       <key column="projectid" />
  10.       <many-to-many class="org.hisp.dhis.user.UserAccess" column="useraccessid" unique="true" />
  11. </set>

但我仍然不确定如何在实体的注解表示中实现它。我已经阅读了关于 @AssociationOverrides 和 @JoinTable 的内容，我知道它们是我需要解决问题的注解，但我仍然无法完全理解。

有人能帮助解释如何正确使用 @AssociationOverrides 和 @JoinTable 并以我的情况为例吗？

英文:

This is my abstract father:

  1. @MappedSuperclass
  2. public class AbstractEntity{
  4.   @ManyToMany
  5.   protected Set&lt;UserGroupAccess&gt; userGroupAccesses = new HashSet&lt;&gt;();
  6.   
  7.   @ManyToMany
  8.   protected Set&lt;UserAccess&gt; userAccesses = new HashSet&lt;&gt;();
  10. }

these are two entities that inherit the AbstractEntity above:

  1. @Entity
  2. public class Project extends AbstractEntity{
  3.     // some other properties
  4. }
  6. @Entity
  7. public class TodoTask extends AbstractEntity{
  8.     // some other properties
  9. }

I want in each subclass entity to override and have its table of the relationship represented by userGroupAccesses and userAccesses, I mean for example for Project Entity I need it to have its own table projectuserGroupAccesses and a table projectuserAccesses representing the relationship defined in the AbstractEntity superclass.

Previously I was able to solve such issue using the XML representation of entities, I just define the following in each entity XML:

  1. &lt;set name=&quot;userGroupAccesses&quot; table=&quot;projectusergroupaccesses&quot; cascade=&quot;all-delete-orphan&quot;&gt;
  2.       &lt;cache usage=&quot;read-write&quot; /&gt;
  3.       &lt;key column=&quot;projectid&quot; /&gt;
  4.       &lt;many-to-many class=&quot;org.hisp.dhis.user.UserGroupAccess&quot; column=&quot;usergroupaccessid&quot; unique=&quot;true&quot; /&gt;
  5.     &lt;/set&gt;
  7.     &lt;set name=&quot;userAccesses&quot; table=&quot;projectuseraccesses&quot; cascade=&quot;all-delete-orphan&quot;&gt;
  8.       &lt;cache usage=&quot;read-write&quot; /&gt;
  9.       &lt;key column=&quot;projectid&quot; /&gt;
  10.       &lt;many-to-many class=&quot;org.hisp.dhis.user.UserAccess&quot; column=&quot;useraccessid&quot; unique=&quot;true&quot; /&gt;
  11.     &lt;/set&gt;

But I still not sure how to do it in the Annotation representation of Entity.
I have read about the @AssociationOverrides and @JoinTable I know they are the one I need to solve my issue, but I still couldn't get my head around them.

Can anyone help to explain how to properly use @AssociationOverrides and @JoinTable using my case as an example?

答案1

得分: 4

最终，我成功地知道了如何完成它。
在我的用例中，我们使用 @AssociationOverrides 和 @JoinTable 来覆盖父类定义的关联关系，具体步骤如下所示：

  1. // 父类
  2. @MappedSuperclass
  3. public class AbstractEntity{
  5.   @Id
  6.   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
  7.   @SequenceGenerator(name = "sequenceGenerator")
  8.   protected Long id; // 我需要在子类实体中覆盖列名。
  10.   @ManyToMany
  11.   protected Set<UserGroupAccess> userGroupAccesses = new HashSet<>(); // 我需要在子类实体中覆盖表名。
  12.   
  13.   @ManyToMany
  14.   protected Set<UserAccess> userAccesses = new HashSet<>(); // 我需要在子类实体中覆盖表名。
  16. }

以下是我需要更改的子类实体示例：

  1. // 第一个子类实体
  2. @Entity
  3. @AttributeOverride(name = "id", column = @Column(name = "projectid"))
  4. @AssociationOverride(
  5.     name="userGroupAccesses",
  6.     joinTable=@JoinTable(
  7.         name="projectusergroupaccesses",
  8.         joinColumns=@JoinColumn(name="projectid"),
  9.         inverseJoinColumns=@JoinColumn(name="usergroupaccessid")
  10.     )
  11. )
  12. @AssociationOverride(
  13.     name="userAccesses",
  14.     joinTable=@JoinTable(
  15.         name="projectuseraccesses",
  16.         joinColumns=@JoinColumn(name="projectid"),
  17.         inverseJoinColumns=@JoinColumn(name="useraccessid")
  18.     )
  19. )
  20. public class Project extends AbstractEntity {
  21.     // 其他属性
  22. }
  24. /////////////////////////
  25. // 第二个子类实体
  27. @Entity
  28. @AttributeOverride(name = "id", column = @Column(name = "todotaskid"))
  29. @AssociationOverride(
  30.     name="userGroupAccesses",
  31.     joinTable=@JoinTable(
  32.         name="todotaskusergroupaccesses",
  33.         joinColumns=@JoinColumn(name="todotaskid"),
  34.         inverseJoinColumns=@JoinColumn(name="usergroupaccessid")
  35.     )
  36. )
  37. @AssociationOverride(
  38.     name="userAccesses",
  39.     joinTable=@JoinTable(
  40.         name="todotaskuseraccesses",
  41.         joinColumns=@JoinColumn(name="todotaskid"),
  42.         inverseJoinColumns=@JoinColumn(name="useraccessid")
  43.     )
  44. )
  45. public class TodoTask extends AbstractEntity {
  46.     // 其他属性
  47. }
英文:

Finally, I managed to know how it's done.
The way we use @AssociationOverrides and @JoinTable in my use case to override the parent-defined relation is as the following:

  1. // Parent class
  2. @MappedSuperclass
  3. public class AbstractEntity{
  5.   @Id
  6.   @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = &quot;sequenceGenerator&quot;)
  7.   @SequenceGenerator(name = &quot;sequenceGenerator&quot;)
  8.   protected Long id; // I need to override the column name in child entities.
  10.   @ManyToMany
  11.   protected Set&lt;UserGroupAccess&gt; userGroupAccesses = new HashSet&lt;&gt;(); // I need to override Table name in child entities.
  12.   
  13.   @ManyToMany
  14.   protected Set&lt;UserAccess&gt; userAccesses = new HashSet&lt;&gt;(); // I need to override Table name in child entities.
  16. }

and the child entities I need to change them as the following:

  1. // First Child Entity
  2. @Entity
  3. @AttributeOverride(name = &quot;id&quot;, column = @Column(name = &quot;projectid&quot;))
  4. @AssociationOverride(
  5.     name=&quot;userGroupAccesses&quot;,
  6.     joinTable=@JoinTable(
  7.         name=&quot;projectusergroupaccesses&quot;,
  8.         joinColumns=@JoinColumn(name=&quot;projectid&quot;),
  9.         inverseJoinColumns=@JoinColumn(name=&quot;usergroupaccessid&quot;)
  10.     )
  11. )
  12. @AssociationOverride(
  13.     name=&quot;userAccesses&quot;,
  14.     joinTable=@JoinTable(
  15.         name=&quot;projectuseraccesses&quot;,
  16.         joinColumns=@JoinColumn(name=&quot;projectid&quot;),
  17.         inverseJoinColumns=@JoinColumn(name=&quot;useraccessid&quot;)
  18.     )
  19. )
  20. public class Project extends AbstractEntity {
  21.     // some other properties
  22. }
  24. /////////////////////////
  25. // Second Child Entity
  27. @Entity
  28. @AttributeOverride(name = &quot;id&quot;, column = @Column(name = &quot;todotaskid&quot;))
  29. @AssociationOverride(
  30.     name=&quot;userGroupAccesses&quot;,
  31.     joinTable=@JoinTable(
  32.         name=&quot;todotaskusergroupaccesses&quot;,
  33.         joinColumns=@JoinColumn(name=&quot;todotaskid&quot;),
  34.         inverseJoinColumns=@JoinColumn(name=&quot;usergroupaccessid&quot;)
  35.     )
  36. )
  37. @AssociationOverride(
  38.     name=&quot;userAccesses&quot;,
  39.     joinTable=@JoinTable(
  40.         name=&quot;todotaskuseraccesses&quot;,
  41.         joinColumns=@JoinColumn(name=&quot;todotaskid&quot;),
  42.         inverseJoinColumns=@JoinColumn(name=&quot;useraccessid&quot;)
  43.     )
  44. )
  45. public class TodoTask extends AbstractEntity {
  46.     // some other properties
  47. }

huangapple
  • 本文由 发表于 2020年8月30日 23:51:47
  • 转载请务必保留本文链接：https://go.coder-hub.com/63659285.html
  • hibernate
  • hibernate-mapping
  • java
  • spring
  • spring-data-jpa
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