Spring JPA SINGLE_TABLE inheritance not working - Table for sub class does not exist

Question

I am trying to utilise Spring JPA inheritance for my entities. Below are the code snippets of the annotations that I use for the classes. The application is based on Spring Boot v2.2.2.RELEASE.

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "entityType", discriminatorType = DiscriminatorType.STRING)
@Getter
@Setter
@NoArgsConstructor
public class RmlAction extends RmlBase {
//attributes
}

Sub-classes: RmlEfsAction.java

@Entity
@Getter
@Setter
@DiscriminatorValue("EFS")
@Table(name = "rml_actions")
@DiscriminatorColumn(name = "entityType", discriminatorType = DiscriminatorType.STRING)
@NoArgsConstructor
public class RmlEfsAction extends RmlAction {
//no attribute
//only constructor
}

RmlProjectAction.java

@Entity
@Getter
@Setter
@DiscriminatorValue("PROJECT")
@Table(name = "rml_actions")
@DiscriminatorColumn(name = "entityType", discriminatorType = DiscriminatorType.STRING)
@NoArgsConstructor
public class RmlProjectAction extends RmlAction {
//no attribute
//only constructor
}

The server starts fine but when I try to do a Data entry, it gives the below error during getting an entity for RmlEfsAction. Any help in identifying the issue is appreciated.

Caused by: org.hibernate.DuplicateMappingException: Duplicate table mapping rml_actions
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.addDenormalizedTable(InFlightMetadataCollectorImpl.java:758)
    at org.hibernate.cfg.annotations.TableBinder.buildAndFillTable(TableBinder.java:499)
    at org.hibernate.cfg.annotations.EntityBinder.bindTable(EntityBinder.java:670)
    at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:603)

Code for fetching entity:

RmlEfsAction dbAction = (RmlEfsAction) actionRepository.getOne(rmlAction.getId());

The error is pretty clear. Do you have a table `rml_action`? If not, add `@Table(...)` to `RmlAction` to point it to the correct table. — Alan Hay, Feb 03 '20 at 08:53
@AlanHay - After code modifications shown above, now i get the error Duplicate table mapping — The Cloud Guy, Feb 03 '20 at 09:35
The code modifications shown above were **add @Table(...) to RmlAction**: not to the subclasses — Alan Hay, Feb 03 '20 at 09:36
@Table must be on the super class as well. Remove it from the sub classes — Simon Martinelli, Feb 03 '20 at 09:36
@AlanHay - If I place `@Table(name="rml_actions")` annotation on just RmlAction - and try to create RmlEfsAction, it gives an error rml_efs_action table does not exist and if i place `@Table(name="rml_actions")` annotation on RmlAction, RmlEfsAction and RmlProjectAction class, I get duplicate mapping error. Kind of caught up in a loop — The Cloud Guy, Feb 03 '20 at 09:45

Spring JPA SINGLE_TABLE inheritance not working - Table for sub class does not exist

0 Answers0