In JPQL the same is actually true in the spec. The JPA spec does not allow an alias to be given to a fetch join. The issue is that you can easily shoot yourself in the foot with this by restricting the context of the join fetch. It is safer to join twice. This is … Read more
The way you have it mapped, the User is the managing side of the relationship, therefore it will be responsible for updating the join table. Change the JoinTable mapping from User to Group, and make the groupList property of User so it has the mappedBy attribute. That will change the group to the managing side … Read more
By default the access type is defined by the place where you put your mapping annotations. If you put them on the field – it will be AccessType.FIELD, if you put them on the getters – it will be AccessType.PROPERTY. Sometimes you might want to annotate not fields but properties (e.g. because you want to … Read more
The Dynamic, typesafe queries in JPA 2.0 article is a very good one on this topic, actually the best one I’ve found so far online, even better than the Chapter 23 Using the Criteria API to Create Queries from the Java EE 6 tutorials (that contains some mistakes).
Fixed it by removing CascadeType.MERGE on Permission entity
I’m pretty sure this has already been covered here on SO but I couldn’t find the existing question. So, here is my point of view on the question: I find JPQL queries easier to write/read. I find the Criteria API nice for building dynamic queries. Which is basically what you’ll find in Hibernate: Criteria vs. … Read more
Like your own question suggests, the key is the domain, not JPA. JPA is just a framework which you can (and should) use in a way which best fits your problem. Choosing a suboptimal solution because of framework (or its limits) is usually a warning bell. When I need a set and never care about … Read more
billProductSet is a Collection. As such, it does not have an attribute named product. Product is an attribute of the elements of this Collection. You can fix the issue by joining the collection instead of dereferencing it: SELECT count(*) FROM BillDetails bd JOIN bd.billProductSet bps WHERE bd.client.id = 1 AND bps.product.id = 1002
My bible for JPA work is the Java Persistence wikibook. It has a section on unidirectional OneToMany which explains how to do this with a @JoinColumn annotation. In your case, i think you would want: @OneToMany @JoinColumn(name=”TXTHEAD_CODE”) private Set<Text> text; I’ve used a Set rather than a List, because the data itself is not ordered. … Read more
JPA 2.0 supports collections of primitives through the @ElementCollection annotation that you can use in conjunction with the support of java.util.Map collections. Something like this should work: @Entity public class Example { @Id long id; // …. @ElementCollection @MapKeyColumn(name=”name”) @Column(name=”value”) @CollectionTable(name=”example_attributes”, joinColumns=@JoinColumn(name=”example_id”)) Map<String, String> attributes = new HashMap<String, String>(); // maps from attribute name to … Read more