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how to find the data by an attribute (name_techno) in jpql

I am developing an application that allows managing candidates in a company, for that I use spring-boot, in order to select the employees who master such a technology (Techno) I used a request JPQL.
So, How can I find a candidate by techno?
In my project I used this code:
1 - the class candidat.java
#Entity
public class Candidat {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name = "candidat_id")
private int id;
private String nom;
private String prenom;
private String ville;
private int numTel;
private String mail;
private String pseudo;
private String roleCible;
private String typeContrat;
private String villeRecherchee;
#OneToMany(mappedBy="candidat")
private List<Techno> techno;
#Temporal(TemporalType.DATE)
private Date date;
#OneToMany
private List<SecteurActivites> secteurActivites;
public Candidat() {
// TODO Auto-generated constructor stub
}
2- the class Techno.java
#Entity
public class Techno {
#Id
#GeneratedValue
#Column(name = "techno_id")
private int id ;
private String nomTechno;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "candidat_id", nullable = false)
#OnDelete(action = OnDeleteAction.CASCADE)
#JsonIgnore
private Candidat candidat;
public Techno() {
// TODO Auto-generated constructor stub
}
/**
* #param nomTechno
* #param candidat
*/
public Techno(String nomTechno, Candidat candidat) {
super();
this.nomTechno = nomTechno;
this.candidat = candidat;
}
3- My CandidatController
#GetMapping(value = "/GetAllCandidats/{nomTechno}")
public List<Candidat> afficherCandidat(#PathVariable ("nomTechno") String nomTechno){
return candidatdao.findByTechno(nomTechno);
}
4- the repository:
#Repository
public interface CandidatDao extends JpaRepository <Candidat, String>{
List<Candidat> findByDate(Date date);
#Query("SELECT DISTINCT e FROM Candidat e INNER JOIN e.Techno t")
List<Candidat> findByTechno(String nomTechno);
}
5- app.properties
server.port= 9090
spring.jpa.show-sql = true
spring.datasource.url= jdbc:mysql://localhost:3306/database
spring.datasource.username=??
spring.datasource.password=??
spring.jpa.hibernate.ddl-auto=update
The result in console is:
"Validation failed for query for method public abstract java.util.List com.avatar.dao.CandidatDao.findByTechno(java.lang.String)!"

You can declare the following method into your JpaRepository (also remove the #Query, it is not needed).
List<Candidat> findDistinctByTechnoNomTechno(String nomTechno);
Also in Techno.java you should add the #Column annotation and map it with the DB schema.
I am not sure if you have pasted incomplete code of your entities on purpose. If not your entities are not correct. You should create setters/getters as the following
private String nomTechno;
#Column(name = "NOM_TECHNO")
public String getNomTechno() {
return nomTechno;
}
public void setNomTechno(String nomTechno){
this.nomTechno = nomTechno;
}
Do the above for all variables in your entities.

You do not need to add explicit #Query for this, Spring data can formulate a query if you have right method names
Instead of
#Query("SELECT DISTINCT e FROM Candidat e INNER JOIN e.Techno t")
List<Candidat> findByTechno(String nomTechno);
Try this
List<Candidat> findDistinctByTechno_NomTechno(String nomTechno);

Hibernate saves additional row instead of updateing and needs two saves

Note: for simplyfication i have changed some variables names and get rid of unnecessary code to show my issue.
I have two repositories:
#Repository
public interface CFolderRepository extends CrudRepository<CFolder, Long>, QuerydslPredicateExecutor<CFolder> {}
#Repository
public interface CRepository extends JpaRepository<C, Long>, CFinder, QuerydslPredicateExecutor<C> {}
The class C is:
#FilterDef(name = "INS_COMPANY_FILTER", parameters = {#ParamDef(name = "insCompanies", type = "string")})
#Filter(name = "INS_COMPANY_FILTER", condition = " INS_COMPANY in (:insCompanies) ")
#NoArgsConstructor
#AllArgsConstructor
#Audited
#AuditOverrides({#AuditOverride(forClass = EntityLog.class),
#AuditOverride(forClass = MultitenantEntityBase.class)})
#Entity
#Table(name = "INS_C")
#Getter
public class C extends MultitenantEntityBase {
#OneToOne(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER, optional = false)
#JoinColumn(name = "C_FOLDER_ID")
private CFolder cFolder;
public void addFolder(List<String> clsUrl){
this.cFolder = CFolder.createFolder(clsUrl);
}
}
CFolder is:
#Getter
#NoArgsConstructor
#Audited
#AuditOverride(forClass = EntityLog.class)
#Entity
#Table(name = "C_FOLDER")
#AllArgsConstructor
public class CFolder extends EntityBase {
#Column(name = "CREATION_FOLDER_DATE_TIME", nullable = false)
private LocalDateTime creationFolderDateTime;
#Column(name = "UPDATED_FOLDER_DATE_TIME")
private LocalDateTime updatedFolderDateTime;
#Column(name = "FOLDER_CREATED_BY", nullable = false)
private String folderCreatedBy;
#Column(name = "FOLDER_UPDATED_BY")
private String folderUpdatedBy;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "cFolder", fetch = FetchType.EAGER)
#NotAudited
private Set<FolderDocument> folderDocuments = new HashSet<>();
public static CFolder createFolder(List<String> clsUrl){
CFolder cFolder = new CFolder(LocalDateTime.now(), null, SecurityHelper.getUsernameOfAuthenticatedUser(), null, new HashSet<>());
createFolderDocuments(clsUrl, cFolder);
return cFolder;
}
public void updateFolder(List<String> clsUrl){
this.updatedFolderDateTime = LocalDateTime.now();
this.folderUpdatedBy = SecurityHelper.getUsernameOfAuthenticatedUser();
this.folderDocuments.clear();
createFolderDocuments(clsUrl, this);
}
private static void createFolderDocuments(List<String> clsUrl, CFolder cFolder) {
int documentNumber = 0;
for (String url : clsUrl) {
documentNumber++;
cFolder.folderDocuments.add(new FolderDocument(cFolder, documentNumber, url));
}
}
}
FolderDocument is:
#Getter
#NoArgsConstructor
#AllArgsConstructor
#Audited
#AuditOverride(forClass = EntityLog.class)
#Entity
#Table(name = "FOLDER_DOCUMENT")
public class FolderDocument extends EntityBase {
#ManyToOne
#JoinColumn(name = "C_FOLDER_ID", nullable = false)
private CFolder cFolder;
#Column(name = "DOCUMENT_NUMBER", nullable = false)
private int documentNumber;
#Column(name = "URL", nullable = false)
private String url;
}
And finally we have a service in which i use these entities and try to save/load them to/from database:
#Service
#AllArgsConstructor(onConstructor = #__(#Autowired))
public class CFolderService {
private final CRepository cRepository;
private final CommunicationClServiceClient communicationServiceClient;
private final CFolderRepository cFolderRepository;
public List<ClDocumentDto> getClCaseFolder(Long cId) {
C insCase = cRepository.findCById(cId);
List<ClDocumentDto> clDocumentsDto = getClDocuments(insCase.getCNumber()); // here, the object has one cFolder, but many FolderDocument inside of it
return clDocumentsDto;
}
#Transactional
public void updateCFolder(Long cId) {
C insC = cRepository.findCById(cId);
List<ClDocumentDto> clDocumentsDto = getClDocuments(insC.getCNumber());
List<String> clsUrl = clDocumentsDto.stream().filter(c -> "ACTIVE".equals(c.getCommunicationStatus())).map(ClDocumentDto::getUrl).collect(Collectors.toList());
if (Objects.isNull(insC.getCFolder())) {
insC.addFolder(clsUrl);
} else {
insC.getCFolder().updateFolder(clsUrl);
}
cFolderRepository.save(insC.getCFolder()); // here it saves additional FolderDocument instead of updateing it
cRepository.save(insC); // need second save, so can get these collection in getClaimCaseFolder successfully
}
}
I have two issues inside. In the example i was trying to clear the objects that i found from DataBase and create new ones.
1)
First is that i have to make two save operation to successfully restore the object in getClCaseFolder method (outside transactional).
2)
Second is that everytime i am saving - i get additional FolderDocument object pinned to CFolder object inside C object. I want to clear this collection and save new one.
I am not sure why hibernate does not update this object?
EDIT:
I think that i do sth like:
cRepository.save(insC);
instead of this.folderDocuments.clear();
i can do:
for(Iterator<FolderDocument> featureIterator = this.folderDocuments.iterator();
featureIterator.hasNext(); ) {
FolderDocument feature = featureIterator .next();
feature.setCFolder(null);
featureIterator.remove();
}
But i get eager fetching, why lazy wont work? There is an error using it.

Check whether you are setting ID in that Entity or not.
If ID is present/set in entity and that ID is also present in DB table then hibernate will update that record, But if ID is not present/set in Entity object the Hibernate always treat that object as a new record and add new record to the table instead of Updating.

Google AppEngine Key exception

I have two classes, CarRentalCompany
#Entity
public class CarRentalCompany {
private static Logger logger = Logger.getLogger(CarRentalCompany.class.getName());
#Id
private String name;
#OneToMany(cascade = CascadeType.ALL)
private List<Car> cars;
#OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private List<CarType> carTypes = new ArrayList<>(); //TODO: kan betere datastructuur zijn
/***************
* CONSTRUCTOR *
***************/
public CarRentalCompany()
{
// DEFAULT CONSTRUCTOR
}
public CarRentalCompany(String name, List<Car> cars) {
logger.log(Level.INFO, "<{0}> Car Rental Company {0} starting up...", name);
setName(name);
this.cars = cars;
for(Car car:cars)
carTypes.add(car.getType());
}
...
}
and CarType
#Entity
public class CarType {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Key key;
private String name;
private int nbOfSeats;
private boolean smokingAllowed;
private double rentalPricePerDay;
//trunk space in liters
private float trunkSpace;
/***************
* CONSTRUCTOR *
***************/
public CarType()
{
}
public CarType(String name, int nbOfSeats, float trunkSpace, double rentalPricePerDay, boolean smokingAllowed) {
this.name = name;
this.nbOfSeats = nbOfSeats;
this.trunkSpace = trunkSpace;
this.rentalPricePerDay = rentalPricePerDay;
this.smokingAllowed = smokingAllowed;
}
When running the application, it throws the following exception:
NucleusFatalUserException: Attempt to assign child with key
"CarType(6614661952700416)" to parent with key
"CarRentalCompany("Hertz")". Parent keys are immutable
What do I need to do to get the key of the CarType right?

You are not persisting your CarRentalCompany entity before adding CarType entity. See a
similar thread here. The persist operation must be used only for new entities. An entity is new when it has never been associated with a database row, meaning that there is no table record in the database to match the entity in question.

Many to Many Hibernate mapping with extra column

I've seen this question on here a few times, however none of the answers fix my issue.
I'm trying to deconstruct a many-to-many relationship down to seperate many-to-one and one-to-many entities so I can add additional columns. From what I have, the main entity saves to the database, but the intermediate does not. If anyone can figure out what's going on I would very much appreciate it. I tried doing this the other way with the primary key composite (aka: #AssociationOverride) but it also did not work. I've scowered the web but cannot find an answer to my issue here.
This is my main entity, MaintOrder:
#Entity
#Table(name="maint_orders")
public class MaintOrder extends PersistedObject implements java.io.Serializable {
...
#OneToMany(cascade = CascadeType.ALL, mappedBy="maintOrder")
private Set<ManPowerLine> manPower = new HashSet<ManPowerLine>() ;
public void addManPower(ManPower manPower, Integer quantity, Float price) {
ManPowerLine mpLine = new ManPowerLine();
mpLine.setManPower(manPower);
mpLine.setMaintOrder(this);
mpLine.setManPowerID(manPower.getManPowerID());
mpLine.setMaintOrderID(this.getMaintOrderID());
mpLine.setQuantity(quantity);
mpLine.setPrice(price);
this.manPower.add(mpLine);
// Also add the association object to the employee.
manPower.getMaintOrder().add(mpLine);
}
... getters and setters
}
Here is my secondary entity, ManPower:
#Entity
#Table(name="man_power")
public class ManPower extends PersistedObject implements java.io.Serializable {
...id's, etc
#OneToMany(mappedBy="manPower", fetch = FetchType.EAGER)
private Set<ManPowerLine> maintOrder = new HashSet<ManPowerLine>();
public Set<ManPowerLine> getMaintOrder(){
return maintOrder;
}
public void setMaintOrder(Set<ManPowerLine> maintOrder){
this.maintOrder = maintOrder;
}
... other getters and setters
}
Here is my intermediate entity, ManPowerLine:
#Entity
#Table(name = "man_power_line")
#IdClass(ManPowerLineID.class)
public class ManPowerLine extends PersistedObject implements java.io.Serializable {
#Id
private Long maintOrderID;
#Id
private Long manPowerID;
#Column(name="quantity")
private Integer quantity;
#Column(name="price")
private Float price;
#ManyToOne
#JoinColumn(name = "maintOrderID", updatable = false, insertable = false, referencedColumnName = "maint_order_id")
private MaintOrder maintOrder;
#ManyToOne
#JoinColumn(name = "manPowerID", updatable = false, insertable = false, referencedColumnName = "man_power_id")
private ManPower manPower;
... other getters and setters
}
And my ID entity, ManPowerLineID:
public class ManPowerLineID implements java.io.Serializable {
private Long maintOrderID;
private Long manPowerID;
public Long getMaintOrderID(){
return maintOrderID;
}
public Long getManPowerID(){
return manPowerID;
}
public void setMaintOrderID(Long maintOrderID){
this.maintOrderID = maintOrderID;
}
public void setManPowerID(Long manPowerID){
this.manPowerID = manPowerID;
}
#Override
public int hashCode(){
return (int)(maintOrderID + manPowerID);
}
#Override
public boolean equals(Object obj) {
if( obj instanceof ManPowerLine){
ManPowerLineID otherID = (ManPowerLineID)obj;
boolean hey = (otherID.maintOrderID == this.maintOrderID) && (otherID.manPowerID == this.manPowerID);
return hey;
}
return false;
}
}
Finally the code which utilizes this is as follows:
private void insertObject( ) {
ServiceLocator locator = new ServiceLocator();
SessionFactory sf = locator.getHibernateSessionFactory();
Session sess = sf.openSession();
Transaction tx = sess.beginTransaction();
MaintOrder m = new MaintOrder();
... various setters to m
Set manPowerSet = new HashSet();
for(int i = 0; i < manPowerSet.size(); i++){
ManPower mp = new ManPower();
mp = (ManPower) manPowerSet.iterator().next();
m.addManPower(mp, quantity, cost);
}
sess.saveOrUpdate(m);
tx.commit();
sess.close();
}
Is it possible that I need to use more then just m.addManPower to add to the line? I've tried adding m.setManPowerLine, but it does not change the result.
Anyways I know its a lot of code to look at, but thanks in advance.

Turns out I fixed my own issue on this one. The problem was that I didn't set cascade = CascadeType.ALL, in ALL the right places. Specifically Here:
#OneToMany(mappedBy="manPower", fetch = FetchType.EAGER)
private List<ManPowerLine> maintOrder = new ArrayList<ManPowerLine>();
Should be:
#OneToMany(mappedBy="manPower", cascade = CascadeType.All)
private List<ManPowerLine> maintOrder = new ArrayList<ManPowerLine>();

Java JPA: adding further objects (products) to a already saved entity (store)

I have a many-to-many relationship between Stores and Products, represented by the following code (mostly based in this answer):
#Entity
#Table(name = "Store")
public class Store {
private long idStore;
// ...
private Collection<StoreHasProduct> storeHasProducts = new ArrayList<>();
#OneToMany(mappedBy = "store", cascade = {CascadeType.MERGE, CascadeType.PERSIST}, fetch = FetchType.EAGER)
public Collection<StoreHasProduct> getStoreHasProducts() {
return storeHasProducts;
}
public void setStoreHasProducts(Collection<StoreHasProduct> storeHasProducts) {
this.storeHasProducts = storeHasProducts;
}
}
#Entity
#Table(name="Product")
public class Product {
private long idProduct;
// ...
private Collection<StoreHasProduct> storeHasProducts = new ArrayList<>();
#OneToMany(mappedBy = "product", fetch = FetchType.LAZY)
public Collection<StoreHasProduct> getStoreHasProducts() {
return storeHasProducts;
}
public void setStoreHasProducts(Collection<StoreHasProduct> storeHasProducts) {
this.storeHasProducts = storeHasProducts;
}
}
#Entity
#Table(name = "Store_has_Product")
#IdClass(StoreHasProductPK.class)
public class StoreHasProduct implements java.io.Serializable {
#Id
#ManyToOne
#JoinColumn(name = "Store_idStore",updatable = true)
private Store store;
#Id
#ManyToOne
#JoinColumn(name = "Product_idProduct", updatable = true)
private Product product;
}
public class StoreHasProductPK implements java.io.Serializable {
private Long store;
private Long product;
}
All basic insertion are working fine. However, when I try to add new Products to a existing Store I'm having a PersistentObjectException: detached entity passed to persist exception. This happens, for example, in the following test:
#Test
public void testAssignProductToAnExistingStore() throws Exception {
//Create a store
Store store = getStore();
//Create and save a product
Product product = getProduct();
StoreHasProduct storeHasProduct = getStoreHasProduct(store, product);
store.getStoreHasProducts().add(storeHasProduct);
storeRepository.save(store);
//Create and save a second product
Product productTwo = getProduct();
Store s = storeRepository.findOne(store.getIdStore());
product.getStoreHasProducts().add(getStoreHasProduct(s, productTwo));
productRepository.save(product);
// s.getStoreHasProducts().add(getStoreHasProduct(s, productTwo));
// storeRepository.save(s);
}
If I try to persist the product, I get detached entity passed to persist: Product. If instead I try to persist the store (commented code) I get the same exception but for store.
What should I do? I'm trying to use the CASCADE.DETACH, but I'm not sure if this is the appropriate path to follow.
Thanks

it's all about configuring Entity manager and/or Transaction manager
take a look
How to save a new entity that refers existing entity in Spring JPA?