I am using Spring Data JPA. Is it possible to use order by at entity level, as we do at collection level
// collection order
#OrderBy("name ASC")
List <Foo> fooList;
I would like to specify order by at entity level
#Entity
#Table(name = "entity" )
// annotation to order by ordinalNo
#Where(clause = "deleted = 0")
public class Entity
private Integer ordinalNo;
Related
I am writing Spring Boot Data JPA application and I have following situation:
I have 2 database queries fetching from same table but they are fetching different columns and data based on their WHERE clauses. For example:
SELECT CAR_TYPE, CAR_MODEL, CAR_YEAR, ACCIDENT_YEAR, BUY_DAY FROM CAR WHERE ACCIDENT_YEAR IS NULL
, and
SELECT CAR_MODEL, CAR_YEAR FROM CAR WHERE CAR_YEAR >= CURRENT_YEAR
As you can see these 2 queries (whose results will be exposed through 2 different API points) reference the same table CAR, but return different fields and have different WHERE clauses.
I know in JPA, I have to create an entity CarEntity like:
#Entity
#Table(name = "CAR")
public class CarEntity {
// I can only have fields from one or the other query
// here, so I guess I have to have 2 of these
}
, but my problem is that this entity needs to apply for the 2 different queries (with different fields returned, different data, different WHERE clauses).
So, it looks like I have to have actually 2 CarEntity classes. But, I am not sure how to make these 2 CarEntities so they both reference the same table CAR?
You can do by using projection that basically you define an interface with field methods which you want to get them. Projections
#Entity
public class Car implement CarSummary { // if you want you can implement JIC
private UUID id;
private String carType;
private String carModel;
private LocalDateTime carYear;
//getters and setters
}
public interface CarSummary {
String getCardModel();
String getCarYear();
}
Then on your query.
public interface CarRepository extends Repository<Car, UUID> {
Collection<CarSummary> findByCarYearGreaterThan(LocalDateTime now);
Collection<Car> findByAccidentYearIsNull();
}
Suppose I have "Account" entity class, and "Transaction" entity class. In table, detail is:
transfer_id
account_from_id
account_to_id
money
565
1
2
12
566
3
1
15
So what annotation or how to code Account entity class, so when I get account.getTransactions, for account_id = 1, it will has 2 transactions? (because both transfer entity involves account id = 1)
#Entity
#Table
public class Account {
// ...
//TODO: How should I do here? Use which annotation or how to do?
private Set<Transfer> transfers;
}
One possible solution is to map "from" and "to" transfers separately:
#Entity
#Table
public class Account {
#OneToMany
#JoinColumn(name = "account_from_id")
private Set<Transfer> fromTransfers;
#OneToMany
#JoinColumn(name = "account_to_id")
private Set<Transfer> toTransfers;
}
But if you need both in one mapped collection you can try something like:
#Entity
#Table
public class Account {
#OneToMany
#JoinFormula("select ts.id from transfer ts where account_from_id = ts.id or account_to_id = ts.id )
private Set<Transfer> transfers;
}
Using javers 5.11.2 I get the following exception although the id is set to be ignored. Why is that?
JaversException ENTITY_INSTANCE_WITH_NULL_ID: Found Entity instance 'my.package.javers.Leaf' with null Id-property 'id'
Update: I learned that
JaVers matches only objects with the same GlobalId
The id is specified using javax.persistence.Id. However, with each ORM it is possible to have an entity with a collection, then add a new element without id to that entity and then save it (CascadeType.Persist).
Is there any way to compare objects with javers in such a case?
Example (used lombok for boiler plate code).
The leaf:
#AllArgsConstructor
#NoArgsConstructor
#Builder
#Data
#Entity
public class Leaf {
#DiffIgnore <============ id is ignored
#Id
private Long id;
private String color;
}
The tree:
#Builder
#Data
#Entity
public class Tree {
#Id
private Long id;
private String name;
#OneToMany
private Set<Leaf> leafs;
}
Test adds a leaf to the oakSecond without an id set. The diff cannot be made. An Exception is thrown.
#Test
public void testCompare_AddLeafToTree() {
Leaf leaf = Leaf.builder().id(1L).color("11").build();
Set<Leaf> leafsOfOakFirst = new HashSet<>();
leafsOfOakFirst.add(leaf);
Tree oakFirst = Tree.builder().id(1L).name("oakFirst").build();
oakFirst.setLeafs(leafsOfOakFirst);
Set<Leaf> leafsOfOakSecond = new HashSet<>();
leafsOfOakSecond.add(leaf);
leafsOfOakSecond.add(Leaf.builder().color("12").build());
Tree oakSecond = Tree.builder().id(1L).name("oakFirst").build();
oakSecond.setLeafs(leafsOfOakSecond);
Javers javers = JaversBuilder.javers().build();
Changes changes = javers.compare(oakFirst, oakSecond).getChanges();
assertThat(changes).isNotEmpty();
}
Same with the following definition of the Javers instance:
EntityDefinition leafEntityDefinition = EntityDefinitionBuilder.entityDefinition(Leaf.class).withIgnoredProperties("id").build();
Javers javers = JaversBuilder.javers().registerEntity(leafEntityDefinition).build();
You can't pass an Entity to Javers with null Id because it would be non-identifiable. If you use Hibernate to generate your Ids, make sure that you pass your object to javers.commit() after hibernate are done with its job. That's how the #JaversSpringDataAuditable aspect works.
Alternatively, you can model those objects with unstable IDs as Value Object in Javers.
I'm using Spring JPA in my DAO layer. I have an entity Projet having inside an entity property Client:
Project.java
#Entity
public class Project {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private int projetId;
private String libelle;
#OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name="client_id")
private Client client;
// ... constructors, getters & setters
}
Client.java
#Entity
public class Client {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private int clientId;
private String denomination;
// ... constructors, getters & setters
}
in my DAO interface I have the following specifications:
ProjetDao.java
#Repository
#Transactional
public interface ProjetDao extends CrudRepository<Projet, Integer> {
#Transactional
public Projet findByLibelle(String libelle);
#Transactional
public Projet findByProjetId(int projetId);
}
My question is: How can I specify in my DAO interface a method that will return all clients distinct in List<Client>?
From the documentation and JIRA:
List<Project> findAllDistinctBy();
The query builder mechanism built into Spring Data repository infrastructure is useful for building constraining queries over entities of the repository. The mechanism strips the prefixes find…By, read…By, query…By, count…By, and get…By from the method and starts parsing the rest of it. The introducing clause can contain further expressions such as a Distinct to set a distinct flag on the query to be created. However, the first By acts as delimiter to indicate the start of the actual criteria. At a very basic level you can define conditions on entity properties and concatenate them with And and Or.
You are dealing with a one-to-one relationship, in this case I guess the list that you need is not really related to specific project, you just want a distinct list of clients.
You will need to create another repository (ClientRepository) for the Client entity and add a findAllDistinct method in this repository.
I am working with Hibernate 4+ Spring MVC + Spring Data with JPA annotations:
#Entity
public class ClassOne implements Serializable{
......
#OneToMany(mappedBy = "mapper", fetch=FetchType.LAZY)
private Set<ClassTwo> element = new HashSet<ClassTwo>(0);
//more fields
//getters and setters
//equals and hashcode
}
#Entity
public class ClassTwo implements Serializable{
......
#ManyToOne(fetch=FetchType.LAZY)
#JoinColumn(name = "CEN_CEN_CODIGO", nullable = false)
private ClassOne classOne;
//more fields
//getters and setters
//equals and hashcode
}
public interface ClassOneRepository extends CrudRepository<ClassOne, Long> {
#Override
#Query("select c from ClassOne c")
public List<ClassOne> findAll();
}
#Service
public class ClassOneService {
#Autowired
private ClassOneRepository classOneRepository;
#Transactional(readOnly=true)
public List<ClassOne> findAll() {
return classOneRepository.findAll();
}
}
And finally I call thie service from my #Controller
#Autowired
ClassOneService classOneService;
I expect results ONLY from ClassOne but retrieving the JOIN values with ClassTwo and all the database tree associate. Is it possible to get only values for ONE table using this schema? Is it a cache problem or Fetching not LAZY?
EDIT: I added the relatioship between two classes
Thank you
You must have the following anotation above your Set<ClassTwo> or its getter:
#OneToMany(fetch = FetchType.LAZY, ...)
See http://docs.oracle.com/javaee/7/api/javax/persistence/OneToMany.html#fetch()
It seems to be that simple "SELECT *" JPA query returns all eagerly fetched fields for the entity.
Please refer to: JPA - Force Lazy loading for only a given query
and http://forcedotcom.github.io/java-sdk/jpa-queries.
So my solution would be to use SessionFactory to get current session and then use "classic" method
return getCurrentSession().createCriteria(persistentClass).list();
Another possible way is to create let's say a POJO object without Set which uses the same table as ClassOne.
I've just added #Lazy for each #ManyToOne and #OneToMany relationship. It seems that Spring Data needs Spring annotations but I supposed that just was necessary to add fetch = FetchType.LAZY. No more Eager behaviours ;).
Thanks for your responses