SpringData - Can a Map<String, @Embedable MyClass> be persisted with @ElementCollection if MyC-CodePudding

I'm currently implementing JPA persistence with Spring Data and I'm not able to solve the following problem so far:

The problem

I have an @Entity EntityClass which has a Map<String, @Embedable MyEmbeddableClass>. This should be simple but MyEmbeddableClass owns its own Map<@Embeddable, Embeddable. Can I achieve this using the @ElementCollection annotation? In other words, can @ElementCollection members own their own collections?

@Entity
public class SimpleClass {
     ...
   @Id
   private Integer id

   @ElementCollection
   @CollectionTable(
      name="simple_class_map",
      joinColumns = {@JoinColumn(name="class_key)}
   )
   private Map<String, MyEmbeddableClass> firstMap;
}

@Embeddable
public class MyEmbeddableClass {
   ...
   @ElementCollection
   @CollectionTable(
      name="simple_class_map",
      joinColumns = {@JoinColumn(name="class_key)}
   )
   private Map<OtherEmbeddableClass, Object> secondMap;
}

@Embeddable
public class OtherEmbeddableClass {
   private String text;
   private String anotherText;
}

CodePudding user response：

No, a member of an @ElementCollection cannot contain another @ElementCollection (at least with Hibernate ORM). This is mentioned in the documentation of Hibernate ORM:

Collections of value type include basic and embeddable types. Collections cannot be nested, and, when used in collections, embeddable types are not allowed to define other collections.

I don't think other JPA implementations support it either (but I might be wrong).