So i have a very basic construction where i have a client and this client could have multiple addresses.
So in hibernate i did something like this
#Entity
#Table(name ="tbl_clients")
#Access(value = AccessType.FIELD)
public class Client {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_client")
private Integer id;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "fkIdClientAddress", cascade = CascadeType.ALL)
private List<AddressClient> addressClientList = new ArrayList<>();
And the other class looks like this :
#Entity
#Table(name ="tbl_clients_address")
#Access(value = AccessType.FIELD)
public class AddressClient {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_client_address")
private Integer id;
#ManyToOne(cascade=CascadeType.ALL)
#JoinColumn(name="id_client")
private Client Client;
#Column
private Integer fkIdClientAddress;
When inserting a client into the database who has 2 addresses it works but the fields fkIdClientAddress and id_client is are empty in the database. So i have no idea to who the address belong.
How can i fix this? And what is wrong with this construction?
first improvements
Class AddressClient
#Entity
#Table(name ="tbl_clients_address")
#Access(value = AccessType.FIELD)
public class AddressClient {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_client_address")
private Integer id;
#ManyToOne
#JoinColumn(name="id_client")
private Client client;
Class Client
#Entity
#Table(name ="tbl_clients")
#Access(value = AccessType.FIELD)
public class Client {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_client")
private Integer id;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "client", cascade = CascadeType.ALL)
private List<AddressClient> addressClientList = new ArrayList<>();
This is looking better but the field id_client is still null
When i created a for each and save the AddressClients again the id is successful saved.
#RequestMapping(value = "/addclient",method = RequestMethod.POST)
public void addClient(#AuthenticationPrincipal Principal user,#RequestBody Client client) {
//FIND THE ACTIVE USER
LOGGER.info("SQL: GET PRINCEPAL USER");
User getuser = userDao.findByEmail(user.getName());
for (AddressClient addressClient : client.getAddressClientList())
{
addressClient.setClient(client);
}
clientDao.save(client);
}
Your mapping is wrong. First of all, you don't need two different columns (id_client and fkIdClientAddress) to know that a given address belongs to a given client. So the first thing to do is to remove fkIdClientAddress.
Then the mappedBy attribute in OneToMany is usd to tell Hibernate which field in address represents the owning ManyToOne association. So it must be set to Client. (or, if you respect the Java naming conventions and rename the field to client, it must be set to client).
Finally, having cascade=ALL on a ManyToOne doesn't make much sense: you don't want to delete the client when you delete one of its addresses. That would fail anyway, since other addresses would still reference the client.
Your mappings are wrong. When you define the collection in Client class, you should indicate the field in the AddressClient class which points back to the Client and that is the field client.
#OneToMany(fetch = FetchType.LAZY, mappedBy = "client", cascade = CascadeType.ALL)
private List<AddressClient> addressClientList = new ArrayList<>();
And in ClientAddress class you have:
#ManyToOne(cascade=CascadeType.ALL)
#JoinColumn(name="id_client")
private Client client;
You do not need the field fkIdClientAddress
In some cases, you still can keep column
#Column
private Integer fkIdClientAddress;
But you have to set data for this column instead of setting value for
private Client client;
But this approach is not appropriate.
Related
I am trying to solve JPA problem. I have 2 main entities - CameraItem and Chain (which represents ordered list of cameras)
Now there have to be 2 #ManyToMany relationships between CameraItem and Chain.
Each CameraItem has at least one parent Chain. As one CameraItem can belong to different Chains, and each Chain can have multiple CameraItems this is the first simple direct #ManyToMany relationship.
Chains can be connected with each other via CameraItem. In other words, CameraItem is holding the connection between Chains. But this is not simple #ManyToMany relationship, because we also need information about direction of the Chains connection. So it is #ManyToMany relationship with new Entity as Baeldung describes here https://www.baeldung.com/jpa-many-to-many. Entity ConnectionPoint is holding the information about the direction as a String.
I paste the classes here:
CHAIN CLASS:
#Entity
#Table(name = "chain")
public class Chain {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Long id;
#NotBlank(message = "Chain name is mandatory")
private String name;
#Column(name = "PLANT_NAME")
private String plantName;
private String description;
private String status;
private Boolean hasPlant;
#CreationTimestamp
#Column(name = "creation_time")
private LocalDateTime creationTime;
#OneToMany(mappedBy = "camera_item")
private List<CameraItem> cameraItems = new ArrayList<>();
#OneToMany(mappedBy = "chain")
Set<ConnectionPoint> connectionPoints;
CAMERA ITEM CLASS:
#Entity
#Table(name = "camera_item")
public class CameraItem {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Long id;
#ManyToOne
#JoinColumn
private Camera camera;
private String name;
private Integer positionInChain;
#ManyToMany(mappedBy = "cameraItems", fetch = FetchType.LAZY)
private List<Chain> parentChainIds;
#OneToMany(mappedBy = "cameraItem")
Set<ConnectionPoint> connectionPoints;
CONNECTION POINT CLASS:
#Entity
#Table(name = "connection_point")
public class ConnectionPoint {
#Id
private Long id;
#Column(name = "direction")
private String direction;
#ManyToOne
#JoinColumn(name = "chain")
private Chain chain;
#ManyToOne
#JoinColumn(name = "camera_item")
private CameraItem cameraItem;
When I run the application I get this error:
org.hibernate.AnnotationException: mappedBy reference an unknown
target entity property:
no.trafsys.videodashboard.model.entity.CameraItem.camera_item in
no.trafsys.videodashboard.model.entity.Chain.cameraItems
Does somebody know where the problem can be?
I use #OneToMany annotations in Chain and CameraItem entities and #ManyToOne in ConnectionPoint like Baeldung in his tutorial.
Thank you in advance for any help
I don't think there is issue in ConnectionPoint. I think the issue is that:
In Chain class,
#OneToMany(mappedBy = "camera_item") // One-to-Many defined here
private List<CameraItem> cameraItems = new ArrayList<>();
while in CameraItem class, corresponding property is defined as follow:
#ManyToMany(mappedBy = "cameraItems", fetch = FetchType.LAZY) // Many-To-Many
private List<Chain> parentChainIds;
Try changing the mapping type to #ManyToMany in Chain class as well. It might work.
PS: I am not entirely sure of this, but this feels like the issue[incorrect mapping type]. Wanted to add this as a comment, but due to space issues, adding it as an answer.
#Entity
#Table(name = "chain")
public class Chain {
//..
#OneToMany(mappedBy = "camera_item")
private List<CameraItem> cameraItems = new ArrayList<>();
//..
}
mappedBy parameter can only be in one side of the relation. I suspect camera_item is database table column name. So your cameraItems needs #JoinTable(name = "camera_item"... annotation
I have two table with many-to-one relationship. Example is, I have Office table and Employee table. One Employee belong to one Office and one Office belong to many Employee.
Office
#Entity(name = "office")
#Table(name = "office", uniqueConstraints = {#UniqueConstraint(columnNames = {"id"})})
public class Office {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "office_name", nullable = false)
private String officeName;
}
Employee
#Entity(name = "employee")
#Table(name = "employee", uniqueConstraints = {#UniqueConstraint(columnNames = {"id"})})
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "employee_name", nullable = false)
private String employeeName;
#ManyToOne(cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
#JoinColumn(name = "office_id", referencedColumnName = "id", nullable = false)
#JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
private Office office;
}
OfficeDto
public class OfficeDto {
private Long id;
private String officeName;
}
EmployeeDto
public class EmployeeDto {
private Long id;
private String employeeName;
private OfficeDto office;
}
With above way of defining the entity and the DTO, when I do employee.findAll(), the JSON result is also include the detail of the office data.
Is there any way that I could achieve (objective):
When do saving new employee, I just have to mention the id of the office.
When do findAll employee, I could choose whether I want to gove the id only or also with the entire object to the client.
Because, with current situation, I think I need to define two employee DTO. First one is contain the entire office data (like the code of EmployeeDto) and the second one is replace private OfficeDto office with private int office.
The second problem you can solve by projection : https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#projections
Or just specific mapper to DTO, for mapping you can use mapstruct : http://mapstruct.org/documentation/installation/
For the first problem i found some answer in stack, but you need verify it : JPA many-to-one relation - need to save only Id
Usually I'm able to Google my way out of asking questions here (thank you SO community), but I'm a bit stuck here. This problem has to do with propagating generated keys to joined objects when calling JpaRepository.save()
We have entities that are defined like so:
Parent object
#Entity
#Table(name = "appointment")
public class Appointment implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "APPT_ID", columnDefinition = "integer")
private Long apptId;
...
#OneToMany(targetEntity = ApptReminder.class, mappedBy = "appointment", cascade = {
CascadeType.MERGE, CascadeType.PERSIST}, fetch = FetchType.EAGER)
#NotFound(action = NotFoundAction.IGNORE)
private List<ApptReminder> apptReminders = new ArrayList<>();
}
Child Object:
#Entity
#Table(name = "appt_reminder")
public class ApptReminder implements Serializable {
#EmbeddedId
private ReminderKey reminderKey = new ReminderKey();
...
#ManyToOne
#NotFound(action = NotFoundAction.IGNORE)
private Appointment appointment;
}
Embedded Id Class
#Embeddable
public class ReminderKey implements Serializable {
#Column(name = "APPT_ID", columnDefinition = "integer")
private Long apptId;
#Column(name = "CALL_NUM", columnDefinition = "integer")
private Short callNum;
....
}
Repository:
public interface AppointmentRepository extends JpaRepository<Appointment, Long> {
}
And we have a bunch of sets of objects hanging off of the child object all sharing the embedded key attributes. When we call save on the parent object appointmentRepository.save(appointment) the child objects get saved, but the appt_id of the first appointment inserted gets an auto generated key of 1, and the first apptReminder record gets an appt_id of 0.
This affects all joined objects that share the embedded ID of ReminderKey with similar and predictable effects.
When we call appoitnmentRepository.save(appointment) on the top level entity, how do we get the autogenerated keys to propagate through to child entities? I feel like this should be very easy. Perhaps there's an element of the way I laid out the mappings or the usage of an embedded id that's preventing this from working.
One last thing of note is that this is running against an H2 database while in development, but will be used against MySQL afterwards. This could be attributable to H2's MySQL compatibility
I think you need to use JoinColumns annotation to marry Appointment apptId to ReminderKey apptId.
Solved this way:
Detach appointment from apptReminder on persist operations:
public class Appointment implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "APPT_ID", columnDefinition = "integer")
private Long apptId;
...
#OneToMany(targetEntity = ApptReminder.class, mappedBy = "appointment", cascade = CascadeType.DETACH, fetch = FetchType.EAGER)
#NotFound(action = NotFoundAction.IGNORE)
private List<ApptReminder> apptReminders = new ArrayList<>();
}
Create a DAO to handle persistence operations:
#Repository
public class AppointmentDAO {
#Autowired
private AppointmentRepository appointmentRepository;
#Autowired
private ApptReminderRepository apptReminderRepository;
public List<Appointment> save(List<Appointment> appointments) {
appointments.forEach(a -> this.save(a));
return appointments;
}
public Appointment save(Appointment appointment) {
final Appointment appt = appointmentRepository.save(appointment);
List<ApptReminder> apptReminders = appointment.getApptReminders();
apptReminders.forEach(a -> {
a.getReminderKey().setApptId(appt.getApptId());
a.getReminderTags().forEach(t -> t.setApptId(appt.getApptId()));
a.getReminderMessages()
.forEach(m -> m.getReminderMessageKey().setApptId(appt.getApptId()));
a.getMsgQueueReminder().setApptId(appt.getApptId());
});
apptReminderRepository.saveAll(apptReminders);
return appointment;
}
}
I have a many to many relation between 2 tables Person and Address with a middle table Person_Address. I have Daos and Services for these entities
What i want to have is when a person is added with an address list if the addresses already exists in the database system should just add id's of those addresses to the Person_Address table.
What happens is duplicate values with different ids.
Possible way to do this is to check the database before adding but if i were to do that then i would be writing my own SQL queries instead of hibernate. Is there a way for me to achieve my objective in hibernate?
Person Class
#Entity
#Table(name = "PERSON")
public class Person {
#Id
#Column(name = "personID")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String name;
private String surName;
#ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
#JoinTable(name = "PERSON_ADDRESS", joinColumns = {
#JoinColumn(name = "PERSONID")}, inverseJoinColumns = {
#JoinColumn(name = "ADDRESSID")})
private List<Address> addresses = new ArrayList<>();
Address Class
#Entity
#Table(name = "ADDRESS")
public class Address {
#Id
#Column(name = "addressID")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#ManyToMany(cascade = CascadeType.ALL, mappedBy = "addresses")
private List<Person> residents;
private String street;
private String state;
private String country;
private String postCode;
If Entity have no ID. Hibernate creates it differently updates.
You should use prefilling of Address in frontend. Or use Criteria API for searching of entered of Address before saving
Maybe one solution can be to change your database and set the complete adress as the primary key, you can get it by concatenating the others fields. To be sure that the adresses will be identical i think you will have to format it to lower or to upper case.
So when you will put the adresse it will be the primary key and you will not have duplicate datas.
In a legacy database, I have three tables: Users, Workgroups, and UsersWorkgroup. UsersWorkgroup stores what role a user has in a workgroup.
Here are the relevant code snippets:
#Entity
#Table(name = "users_workgroup")
public class UsersWorkgroup implements Serializable {
private static final long serialVersionUID = 1L;
#EmbeddedId
protected UsersWorkgroupPK usersWorkgroupPK;
#JoinColumn(name = "idworkgroup", referencedColumnName = "idworkgroup")
#ManyToOne(optional = false)
private Workgroup workgroup;
#JoinColumn(name = "user_name", referencedColumnName = "user_name")
#ManyToOne(optional = false)
private Users users;
#Column(name = "role")
private Integer role;
#Embeddable
public class UsersWorkgroupPK implements Serializable {
#Basic(optional = false)
#Column(name = "idworkgroup", insertable=false, updatable=false)
private int idworkgroup;
#Basic(optional = false)
#Column(name = "user_name", insertable=false, updatable=false)
private String userName;
#Entity
#Table(name = "workgroup")
public class Workgroup implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Basic(optional = false)
#Column(name = "idworkgroup")
private Integer idworkgroup;
#Column(name = "name")
private String name;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "idworkgroup")
private Collection<UsersWorkgroup> usersWorkgroupCollection;
And of course, problem is, it doesn't work.
Currently I get this exception:
Exception Description: An incompatible
mapping has been encountered between
[class entity.Workgroup] and [class
entity.UsersWorkgroup]. This usually
occurs when the cardinality of a
mapping does not correspond with the
cardinality of its backpointer.
Which I don't understand since OneToMany should match ManyToOne... Or is it a ManyToMany relationship? If I switch to #ManyToMany, I get this:
Exception Description: The target
entity of the relationship attribute
[workgroup] on the class [class
com.ericsson.rsg.ejb.entity.UsersWorkgroup]
cannot be determined. When not using
generics, ensure the target entity is
defined on the relationship mapping.
I'm trying to understand compound keys (embedded), but all the examples I could find have only simple columns that are not foreign keys (but that's the whole point of a compound key, isn't it?). Can the UsersWorkgroup table secretly be a join table?
Should I declare the PK class as a strict POJO class? Or should I put the #JoinColumn annotations in the PK class? How do I refer to the columns within the compound key from another table? Should I initialize the PK object in the refering class constructor, or is it not necessary?
I feel stuck completely.
First of all, I think your relation is a Many To Many, as a user can be in many groups, and a group can have many users (or I would assume so).
Second, as far as I know you have to reference both id_workgroup and user_name as JoinColumns, because they are part of the PK and a unit, so both should be referenced.
Also, I see the "equals" and "hashCode" methods missing from your embedded PK, as well as the getters/setters. I believe they are mandatory.
Your mapping looks fine except for mappedBy - it should be a property name, not a column name:
#OneToMany(cascade = CascadeType.ALL, mappedBy = "workgroup")
private Collection<UsersWorkgroup> usersWorkgroupCollection;