The exception message says: Books is not mapped [SELECT COUNT(*) FROM Books]; nested exception is org.hibernate.hql.ast.QuerySyntaxException: Books is not mapped [SELECT COUNT(*) FROM Books] Books is not mapped. That is, that there is no mapped type called Books. And indeed, there isn’t. Your mapped type is called Book. It’s mapped to a table called Books, … Read more
This can be solved by adding the following annotation to the UUID: import org.hibernate.annotations.Type; … @Type(type=”pg-uuid”) private java.util.UUID itemUuid; As to why Hibernate doesn’t just make this the default setting, I couldn’t tell you… UPDATE: There still seem to be issues using the createNativeQuery method to open objects that have UUID fields. Fortunately, the createQuery … Read more
Check all of the places where you are assigning something to sonEntities. The link you referenced distinctly points out creating a new HashSet but you can have this error anytime you reassign the set. For example: public void setChildren(Set<SonEntity> aSet) { this.sonEntities = aSet; //This will override the set that Hibernate is tracking. } Usually … Read more
EDIT 2017-04-29: As pointed to by some of the commenters, the JoinTable example does not need the mappedBy annotation attribute. In fact, recent versions of Hibernate refuse to start up by printing the following error: org.hibernate.AnnotationException: Associations marked as mappedBy must not define database mappings like @JoinTable or @JoinColumn Let’s pretend that you have an … Read more
MappedBy signals hibernate that the key for the relationship is on the other side. This means that although you link 2 tables together, only 1 of those tables has a foreign key constraint to the other one. MappedBy allows you to still link from the table not containing the constraint to the other table.
JPA doesn’t offer any support for derived property so you’ll have to use a provider specific extension. As you mentioned, @Formula is perfect for this when using Hibernate. You can use an SQL fragment: @Formula(“PRICE*1.155”) private float finalPrice; Or even complex queries on other tables: @Formula(“(select min(o.creation_date) from Orders o where o.customer_id = id)”) private … Read more