You should provide exactly the model the view expects. If the JPA entity happens to match exactly the needed model, then just use it right away. If the JPA entity happens to have too few or too much properties, then use a DTO (subclass) and/or a constructor expression with a more specific JPQL query, if … Read more
Use the select new map syntax in HQL to fetch the results of each row in a Map. Take a look at the following question, that addresses the issue: How to fetch hibernate query result as associative array of list or hashmap. For instance, the following HQL: select new map(perm.id as pid, perm.name as pname) … Read more
There are several ways to implement a one-to-one association in a database: you can share a primary key but you can also use a foreign key relationship with a unique constraint (one table has a foreign key column that references the primary key of the associated table). In the later case, the hibernate way to … Read more
It is there to specify another column as the default id column of the other table, e.g. consider the following TableA id int identity tableb_key varchar TableB id int identity key varchar unique // in class for TableA @JoinColumn(name=”tableb_key”, referencedColumnName=”key”)
I think I’ve found the answer myself. If somebody finds this question, here’s my answer. How does Spring manage Hibernate Sessions? By default, Spring Boot applies transaction management at the repository level. In this case, when calling a JpaRepository method (or in general any Repository method), Spring will: Ask the SessionFactory to create a new … Read more
You are missing a field annotated with @Id. Each @Entity needs an @Id – this is the primary key in the database. If you don’t want your entity to be persisted in a separate table, but rather be a part of other entities, you can use @Embeddable instead of @Entity. If you want simply a … Read more
according to the book “Pro EJB 3 Java Persistence API” Constructor Expressions A more powerful form of SELECT clause involving multiple expressions is the constructor expression, which specifies that the results of the query are to be stored using a user-specified object type. Consider the following query: SELECT NEW example.EmployeeDetails(e.name, e.salary, e.department.name) FROM Employee e … Read more
Remove the following line, it interferes with Spring-managed transactions: <property name=”current_session_context_class”>thread</property>
For any Hibernate 5.x users, there is <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-java8</artifactId> <version>5.0.0.Final</version> </dependency> You don’t need to do anything else. Just add the dependency, and the Java 8 time types should work like any other basic types, no annotations required. private LocalDateTime invalidateTokenDate; Note: this won’t save to timestamp type though. Testing with MySQL, it saves … Read more
Using annotation mappings as an example: Configuration cfg1 = new AnnotationConfiguration(); cfg1.configure(“/hibernate-oracle.cfg.xml”); cfg1.addAnnotatedClass(SomeClass.class); // mapped classes cfg1.addAnnotatedClass(SomeOtherClass.class); SessionFactory sf1 = cfg1.buildSessionFactory(); Configuration cfg2 = new AnnotationConfiguration(); cfg2.configure(“/hibernate-mysql.cfg.xml”); cfg2.addAnnotatedClass(SomeClass.class); // could be the same or different than above cfg2.addAnnotatedClass(SomeOtherClass.class); SessionFactory sf2 = cfg2.buildSessionFactory(); Then use sf1 and sf2 to get the sessions for each database. For … Read more