I have two entities, let's say
Person.java:
#Entity
public class Person implements Serializable {
#Id
#GeneratedValue(strategy = AUTO)
private long id;
#OneToMany(mappedBy = "personData", cascade = CascadeType.PERSIST)
private List<SkillsData> skillsData;
// ...
}
SkillsData.java
#Entity
#Table(name = "SkillsData")
public class SkillsData implements Serializable {
#Id
#GeneratedValue(strategy = AUTO)
private long id;
#JoinColumn(name = "PERSONID")
#ManyToOne(cascade = REMOVE)
private Person personData;
// ...
}
When I create a person, add a list of type SkillsData to it's skillsData field and persist it everything works with no exceptions thrown, but when I browse the database directly in the SkillsData table the field PERSONID is not populated and because of that the skills added can't be referenced to the right person.
I'm trying to fix this problem for quite some time and I'll be thankful for any help.
The problem might be in the fact that you're not setting SkillsData.personData before persisting leaving it null.
You must set it cause adding SkillsData to the Person.skillsData list is not enough since you declared this side of relationship as inverse(mappedBy attribute).
Therefore it is the SkillsData.personData non-inverse side who is responsible for establishing this relationship.
Related
I have two entities mapped to one another using the oneToMany annotation. One entity is bookedBus and the second is drivers The drivers entity would already have a row inserted into that would later become a foreign reference (FK) to bookedBus entity(PK). Below are the two entities, setters and getter have been skipped for brevity.
First entity
#Entity
#Table(name = "bookedBuses")
public class BookedBuses implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "driver_id")
private Drivers driver;
}
Second entity
#Entity
public class Drivers implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "driver")
private List<BookedBuses> bookedBus;
}
Now When I try to save to the booked bus entity it throws the following exception
org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.bus.api.entity.Drivers; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.bus.api.entity.Drivers
Below is how I tried saving to the bookedBus entity
BookedBuses bookedRecord = new BookedBuses();
bookedRecord.setBookedSeats(1);
bookedRecord.setBookedBusState(BookedBusState.LOADING);
bookedRecord.setBus(busService.getBusByPlateNumber(booking.getPlateNumber()));
bookedRecord.setRoute(booking.getRoute());
infoLogger.info("GETTING DRIVER ID ======= " + booking.getDriver().getId());
Drivers drivers = new Drivers(booking.getDriver().getId());
List<BookedBuses> d_bu = new ArrayList<>();
drivers.setBooked(d_bu);
drivers.addBooked(bookedRecord);
bookedRecord.setDriver(drivers);
bookedBusService.save(bookedRecord);
My BookBusService Save Method as requested
#Autowired
private BookedBusRepository bookedBusRepo;
public boolean save(BookedBuses bookedRecord) {
try {
bookedBusRepo.save(bookedRecord);
return true;
} catch (DataIntegrityViolationException ex) {
System.out.println(ex);
AppConfig.LOGGER.error(ex);
return false;
// Log error message
}
}
1st you have some mix up in naming: you have Driver & Drivers. Like this:
private Drivers driver;
Also selecting variable names like this:
BookedBuses bookedRecord = new BookedBuses();
will cause a lot of confusion. Do not mix plural & singular between types and preferably also do not introduce names that might not be easily associated like record. Also this:
private List<BookedBuses> bookedBus;
which should rather be like:
private List<BookedBus> bookedBuses;
(and would alsoi require change to your class name BookedBuses -> BookedBus)
Anyway the actual problem seems to lie here:
Drivers drivers = new Drivers(booking.getDriver().getId());
You need to fetch existing entity by id with a help of repository instead of creating a new one with id of existing. So something like:
Drivers drivers = driverRepo.findOne(booking.getDriver().getId()); // or findById(..)
It seems that you have a constructor (that you did not show) that enables to create a driver with id. That is not managed it is considered as detached. (You also have drivers.addBooked(bookedRecord); which you did not share but maybe it is trivial)
Note also some posts suggest to changeCascadeType.ALL to CascadeType.MERGE whether that works depends on your needs. Spring data is able to do some merging on save(..) based on entity id but not necessarily in this case.
This line
Drivers drivers = new Drivers(booking.getDriver().getId());
If you already have the driver ID available with you then there's no need to pull the driver ID again from the DB.
After removing the Cascade attribute from #OneToMany & #ManyToOne your code should work.
#Entity
#Table(name = "bookedBuses")
public class BookedBuses implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
`
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "driver_id")
private Drivers driver;
}
#Entity
public class Drivers implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(fetch = FetchType.LAZY)
#JoinColumn(name = "driver_id")
private List<BookedBuses> bookedBus;
}
I have been trying to solve this for whole day but no luck! Also i tried to read most of the tutorials on the net but as you all know they all are full of useless examples that do not reflect what you need in the real world.
So here is my situation:
The database:
table: vehicles(vehicleId, brand, model, devYear, regNumber) <-- vehicleId is the PrimaryKey
table: extras(vehicleId, allowSmoke, allowFood, allowDrinks, airConditioner) <-- vehicleId is a PK and a FK.
The point is that if i have a class Vehicle and a class TravelExtras which are mapped to the database i want the Vehicle class to have an attribute TravelExtras travelExtras and get and set methods.
Unfortunatelly no matter what i tried when i try to persist the object in the databse i get various errors.
Here is an illustration:
EntityManagerFactory emfactory = Persistence.createEntityManagerFactory( "NaStopPU" );
EntityManager entitymanager = emfactory.createEntityManager( );
entitymanager.getTransaction( ).begin( );
TravelExtra travelExtra = new TravelExtra();
entitymanager.persist(travelExtra);
Vehicle vehicle = new Vehicle(2L, "10152487958556242", "Mazda", "626", "334343", 2005, 4);
vehicle.setTravelExtra(travelExtra);
entitymanager.persist(vehicle);
entitymanager.getTransaction().commit();
entitymanager.close( );
emfactory.close( );
Any one knows what kind of annotations to use for this One to one case ?
The Java Persistence wikibook has a section called Primary Keys through OneToOne and ManyToOne Relationships which seems to indicate that what you want is possible.
If I'm reading it right, for your case, it would look something like:
class Vehicle {
#Id
#Column(name = "EXTRAS_ID")
private long extrasId;
#OneToOne(mappedBy="vehicle", cascade=CascadeType.ALL)
private TravelExtra extras;
}
class TravelExtras {
#Id
#Column(name = "VEHICLE_ID")
private long vehicleId;
#OneToOne
#PrimaryKeyJoinColumn(name="VEHICLE_ID", referencedColumnName="EXTRAS_ID")
private Vehicle vehicle;
public TravelExtras(Vehicle vehicle) {
this.vehicleId = vehicle.getId();
this.vehicle = vehicle;
}
}
Note that one of your entities will need to make sure it has the same id as the other, which is accomplished in the example by the TravelExtras constructor requiring the Vehicle it is bound to.
I know this is very old qs, but for completeness of your case
you can just have (jpa 2.0)
#Entity
#Data
public class Vehicle implements Serializable{
#Id
#GeneratedValue
private long vehicleId;
.. //other props
}
#Entity
#Data
public class VehicleExtras implements Serializable{
#Id
#OneToOne (cascade = CASCADE.ALL)
#MapsId
#JoinColumn(name ="vehicleId")
private Vehicle vehicle;
#Column
private boolean allowSmoke;
..// other props.
}
should share same pk/fk for VehicleExtra table
Why don't you use an #Embedded object? When using an embedded object, you get
the logical separation you desire in your code and keep your database compliant with Entity-Relational Normalization rules.
It's weird to think on a One-to-One relationship, because even though JPA/Hibernate allows it, all data should be stored in the same table, making you model simpler, while also simplifying queries and increasing database performance by removing the need for a Join operation.
When using Embedded objects you don't have to worry about mapping IDs and bizarre relations, since your ORM is capable of understanding that your just making a code separation, instead of demanding an actual relation of One-to-One between tables.
class Vehicle {
#Id
#Column(name = "ID")
private long vehicleId;
#Column(name = "BRAND")
private String brand;
#Column(name = "MODEL")
private String model;
#Column(name = "DEV_YEAR")
private int devYear;
#Column(name = "REG_NUMBER")
private int regNumber;
#Embedded
private TravelExtra extras;
// Constructor, getters and setters...
}
.
#Embeddable
class TravelExtras {
#Column(name = "ALLOW_SMOKE")
private boolean allowSmoke;
#Column(name = "ALLOW_FOOD")
private boolean allowFood;
#Column(name = "ALLOW_DRINKS")
private boolean allowDrinks;
#Column(name = "AIR_CONDITIONER")
private boolean airConditioner;
// Default Constructor, getters and setters...
}
You can map your classes for example with Netbeans. It will generate annotations. The problem could be your dao layer. You have to persist objects in correct way. For example can't save travelExtra without Vehicle. Also be aware of owning side.
I'm trying to write a hibernate adapter for an old database schema. This schema does not have a dedicated id column, but uses about three other columns to join data.
On some tables, I need to use coalesce. This is what I came up with so far:
About the definition:
A car can have elements, assigned by the car's user or by the car's group of users.
If FORIGN_ELEMENT holds a user's name, definition will be 'u'
If FORIGN_ELEMENT holds a group's name, definition will be 'g'
This also means, one table (CAR_TO_ELEMENT) is misused to map cars to elements and cargroups to elements. I defined a superclass CarElement and subclasses CarUserElement and CarGroupElement.
state is either "active" or an uninteresting string
I set definitition and state elsewhere, we do not need to worry about this.
Use DEP_NR on the join table. If it's zero, use USR_DEP_NR. I did this with COALESCE(NULLIF()) successfully in native SQL and want to achieve the same in Hibernate with Pojos.
Okay, here we go with the code:
#Entity
#Table(name="CAR")
public class Car extends TableEntry implements Serializable {
#Id
#Column(name="DEP_NR")
private int depnr;
#Id
#Column(name="USER_NAME")
#Type(type="TrimmedString")
private String username;
#ManyToOne(fetch = FetchType.EAGER, targetEntity=CarGroup.class)
#JoinColumns(value={
#JoinColumn(name="GROUP_NAME"),
#JoinColumn(name="DEP_NR"),
#JoinColumn(name="state"),
})
private CarGroup group;
#OneToMany(fetch=FetchType.EAGER, targetEntity=CarUserElement.class, mappedBy="car")
private Set<CarUserElement> elements;
}
#Entity
#Table(name="CAR_GROUP")
public class CarGroup extends TableEntry implements Serializable {
#Id
#Column(name="DEP_NR")
private int depnr;
#Id
#Column(name="GROUP_NAME")
#Type(type="TrimmedString")
private String group;
#ManyToOne(fetch = FetchType.EAGER, targetEntity=Car.class)
#JoinColumns(value={
#JoinColumn(name="GROUP_NAME"),
#JoinColumn(name="DEP_NR"),
#JoinColumn(name="state"),
})
private Set<Car> cars;
#OneToMany(fetch=FetchType.EAGER, targetEntity=CarGroupElement.class, mappedBy="car")
private Set<CarGroupElement> elements;
}
#MappedSuperclass
public class CarElement extends TableEntry {
#Id
#ManyToOne(fetch = FetchType.EAGER, targetEntity=Element.class)
#JoinColumns(value={
#JoinColumn(name="ELEMENT_NAME"),
#JoinColumn(name="state"),
})
private Element element;
}
#Entity
#Table(name="CAR_TO_ELEMENT")
public class CarUserElement extends CarElement {
#Id
#Column(name="DEFINITION")
private char definition;
#Id
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumnsOrFormulas(value = {
#JoinColumnOrFormula(formula=#JoinFormula(value="COALESCE(NULLIF(DEP_NR, 0), USR_DEP_NR)", referencedColumnName="DEP_NR")),
#JoinColumnOrFormula(column=#JoinColumn(name="FORIGN_ELEMENT", referencedColumnName="USER_NAME")),
#JoinColumnOrFormula(column=#JoinColumn(name="STATE", referencedColumnName="STATE"))
})
private Car car;
}
#Entity
#Table(name="CAR_TO_ELEMENT")
public class CarGroupElement extends CarElement {
#Id
#Column(name="DEFINITION")
private char definition;
#Id
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumnsOrFormulas(value = {
#JoinColumnOrFormula(formula=#JoinFormula(value="COALESCE(NULLIF(DEP_NR, 0), USR_DEP_NR)", referencedColumnName="DEP_NR")),
#JoinColumnOrFormula(column=#JoinColumn(name="FORIGN_ELEMENT", referencedColumnName="GROUP_NAME")),
#JoinColumnOrFormula(column=#JoinColumn(name="STATE", referencedColumnName="STATE"))
})
private Car car;
}
I tried all available versions of hibernate (from 3.5.1 [first version with #JoinColumnsOrFormulas] up to 4.x.x), but I always get this error:
Exception in thread "main" java.lang.ClassCastException: org.hibernate.mapping.Formula cannot be cast to org.hibernate.mapping.Column
at org.hibernate.cfg.annotations.TableBinder.bindFk(TableBinder.java:351)
at org.hibernate.cfg.annotations.CollectionBinder.bindCollectionSecondPass(CollectionBinder.java:1338)
at org.hibernate.cfg.annotations.CollectionBinder.bindOneToManySecondPass(CollectionBinder.java:791)
at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:719)
at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:668)
at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:66)
at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1597)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1355)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1737)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1788)
Other hibernate users seem to have the same problem: They can't get it working with any version, see this thread and other stackoverflow questions:
https://forum.hibernate.org/viewtopic.php?f=1&t=1010559
To be more complete, here's my TrimmedString Class:
https://forum.hibernate.org/viewtopic.php?p=2191674&sid=049b85950db50a8bd145f9dac49a5f6e#p2191674
Thanks in advance!
PS: It works with joining just these three colulmns with just one DEP-NR-Column (i.e. either DEP_NR OR USR_DEP_NR using just #JoinColumns). But I need this coalesce(nullif()).
I ran into a similar problem, and it seems that the issue is that you are using a #Formula inside an #Id. Hibernate wants Ids to be insertable, and Formulas are read-only.
In my case I was able to work around the problem by making the individual columns Id properties on their own, and making the joined object a separate property. I don't know if this would work in your case since you're using two different columns in your formula, but if so your code might look something like:
#Entity
#Table(name="CAR_TO_ELEMENT")
public class CarUserElement extends CarElement {
#Id
#Column(name="DEFINITION")
private char definition;
#Id
#Column(name="DEP_NR")
private Integer depNr;
#Id
#Column(name="USR_DEP_NR")
private Integer usrDepNr;
#Id
#Column(name="FORIGN_ELEMENT")
private String userName;
#Id
#Column(name="STATE")
private String state;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumnsOrFormulas(value = {
#JoinColumnOrFormula(formula=#JoinFormula(value="COALESCE(NULLIF(DEP_NR, 0), USR_DEP_NR)", referencedColumnName="DEP_NR")),
#JoinColumnOrFormula(column=#JoinColumn(name="FORIGN_ELEMENT", referencedColumnName="USER_NAME", insertable = false, updatable = false)),
#JoinColumnOrFormula(column=#JoinColumn(name="STATE", referencedColumnName="STATE", insertable = false, updatable = false))
})
private Car car;
}
Join formulas are very fragile in Hibernate for the time being; I always had a difficult time to get them work properly.
The workaround that helped me often was to create database views which exposed the proper columns (including foreign keys that don't exist in the original tables). Then I mapped the entities to the views using classing Hibernate/JPA mappings.
Sometimes there are redundant joins in the generated SQL when using such entities, but the database optimizes such queries in most cases so that the execution plan is optimal anyway.
Another approach could be using #Subselects, which are some kind of Hibernate views, but I expect them to be less performant than the classic database views.
I ran into the cast exception as well and I'm on Hibernate 5.x.
Until Hibernate dedicates time to fix the issue, I found that while this guy's approach may not be cleanest (he even eludes to that fact!), it works.
You just need to add the #Column mappings (and get/set methods) to your association table objects that are returning null and manually set the values when you populate the relation data. Simple but effective!
I have searched and found similar issues, but they don't quite seem to be the same problem as
Why am I getting this NullPointer exception?
OneToOne Mapping with hibernate/JBoss/Seam
ANN-613 - NPE when mappedBy property is wrong on a #OneToOne
ANN-558 - #OneToMany(mappedBy="") can not recognize properties in parent classes
Hibernate Users - NPE with #Id on #OneToOne
I have a few entities mapped like this:
Person
|
+--User
I want to add a new entity PersonPartDeux with a OneToOne mapping to Person. The resulting mapping should look something like this:
Person + PersonPartDeux
|
+--User
When I do so, a NullPointerException is thrown while trying to load the mapping:
java.lang.NullPointerException
at org.hibernate.cfg.OneToOneSecondPass.doSecondPass(OneToOneSecondPass.java:135)
How do I specify the mapping so I can avoid this exception?
Here's my code:
#Entity
#Inheritance(strategy = InheritanceType.JOINED)
public abstract class Person implements Serializable
{
#Id
#GeneratedValue
public Long id;
#Version
public int version = 0;
public String name;
#OneToOne(cascade = CascadeType.ALL)
#PrimaryKeyJoinColumn
public PersonPartDeux personPartDeux;
}
#Entity
public class PersonPartDeux implements Serializable
{
#Id
#GeneratedValue(generator = "person-primarykey")
#GenericGenerator(
name = "person-primarykey",
strategy = "foreign",
parameters = #Parameter(name = "property", value = "person")
)
public Long id = null;
#Version
public int version = 0;
#OneToOne(optional=false, mappedBy="person")
public Person person;
public String someText;
}
#Entity
#PrimaryKeyJoinColumn(name = "person_Id")
public class User extends Person
{
public String username;
public String password;
}
As for why I'm bothering, I need both the inheritance and the OneToOne mapping to solve different known issues in my application.
Attach the Hibernate source to your project, so you can click thru or 'Open Type' (Ctrl-Shift-T in Eclipse) to view the OneToOneSecondPass source.
Seeing the source, will give you a clear indication as to what needs to be specified.
In my source (Hibernate 4.1.7), line 135 is
propertyHolder.addProperty( prop, inferredData.getDeclaringClass() );
However you're probably using an earlier version.
Looking at the mappings, I'm suspicious of the #OneToOne definition -- mappedBy="person".
#OneToOne(optional=false, mappedBy="person")
public Person person;
What does it usefully mean, to map an association property by itself? Hibernate already knows the property is a OneToOne -- you just told it that.
Pointing the underpinning mapping/ FK of the property, at itself.. probably isn't actually telling Hibernate any correct or useful information.
Here's an example from the HB dosc, perhaps showing better how to do what you want:
#Entity
class MedicalHistory implements Serializable {
#Id Integer id;
#MapsId #OneToOne
#JoinColumn(name = "patient_id")
Person patient;
}
#Entity
class Person {
#Id #GeneratedValue Integer id;
}
Source: http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/
(3.5 docs off JBoss site.)
Cheers, hope this helps.
I am having troubles getting this working and I wonder if what I am doing simply does not make sense?
public class Application {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="id")
private long id;
....
}
#MappedSuperclass
public abstract class Sample {
#Id #GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#OneToOne (cascade=CascadeType.ALL)
protected Application application;
....
}
// TestSample contains a list that is mapped not by the primary key of the Sample
public class TestSample extends Sample {
#OneToMany(mappedBy="application", cascade=CascadeType.ALL, fetch=FetchType.LAZY)
private List<Part> parts = new ArrayList<Part>();
....
}
public class Part {
#Id #GeneratedValue(strategy = GenerationType.AUTO)
private long id = 0;
#ManyToOne (cascade=CascadeType.ALL, fetch=FetchType.LAZY)
Application application;
}
The problem I am having is that I am able to add parts, the database looks correct, then when I attempt to fetch the the parts list I get an empty list.
I can get it to work if I compromise on the database structure by changing these classes:
// TestSample contains a list that is mapped not by the primary key of the Sample
public class TestSample extends Sample {
#OneToMany(mappedBy="testSample", cascade=CascadeType.ALL, fetch=FetchType.LAZY)
private List<Part> parts = new ArrayList<Part>();
....
}
public class Part {
#Id #GeneratedValue(strategy = GenerationType.AUTO)
private long id = 0;
#ManyToOne (cascade=CascadeType.ALL, fetch=FetchType.LAZY)
TestSample testSample;
}
The tables are being auto generated by hibernate, so they are coming out like this:
application
id : number
....
test_sample
id : number
application_id : number
...
part
id : number
application_id : number
If I change it to the less desirable way that works, the last table is different:
part
id : number
test_sample_id : number
Because the id's in all cases are being auto generated, there are no shared primary keys. Essentially what I am trying to do is use mappedby where mappedby is referring to a field that is not the primary key of the table/class called "TestSample". This is what I am not sure if makes sense in JPA.
The OneToMany is bi-directional with the "Part" class. I think this is getting very difficult to explain (:
Your one-to-many association between TestSample and Part is not bidirectional, the mappedBy is not correct (the application table is not owning the relation, it is not even aware of test_sample), your mapping doesn't make sense. There is something to change.
I think that you should show what the expected tables are, not the generated one (since the mappings are incoherent, the generated result can't be satisfying). You are talking about compromise so I believe that you have an idea of what the expected result should be. Please show it.