I have a bean structure as shown below. The problem that I am facing is while trying to persist XBean, I am able to save all the data (i.e. xName, pBean, qBean, rBean, kBeans are all visible in storage) but there is no entry for Y_BEAN.
I am pretty much new with JPA annotations so not really sure if what I have done is correct. The idea is to have multiple entries of XBean (i.e. as List) with one instance of YBean
XBean also will hold an instance of YBean as its parent so when I retrieve XBean I should get all the data. Is there something wrong with #ManyToOne annotation?
#Entity
#Table (name = "X_BEAN")
public class XBean implements XInterface {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Key key;
private String xName;
#OneToOne(cascade=CascadeType.ALL)
private PBean pBean;
#ManyToOne
#JoinColumn(name="y_id")
private YBean yBean;
#OneToOne(cascade=CascadeType.ALL)
private qBean qBean;
#OneToOne(cascade=CascadeType.ALL)
private RBean rBean;
#OneToMany (mappedBy="xBean", cascade=CascadeType.ALL)
private List<KBean> kBeans;
// getter setters for each are below ...
}
and structure of YBean is like below
#Entity
#Table (name = "Y_BEAN")
public class YBean implements XInterface {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Key key;
#OneToOne(cascade=CascadeType.ALL)
private ZBean zName;
#OneToOne(cascade=CascadeType.ALL)
private PBean pBean;
#OneToOne(cascade=CascadeType.ALL)
private RBean rBean;
#OneToMany (mappedBy="yBean", cascade=CascadeType.ALL)
private List<XBean> xBeans;
// getter setter for each are below ...
}
I am using Google App Engine's storage
You need cascade=CascadeType.PERSIST on your ManyToOne, to tell Hibernate to persist the YBean when it persists the XBean.
You should also think about whether you want the cascade attribute on the inverse OneToMany. With CascadeType.ALL, if you were to delete an instance of YBean, Hibernate will delete all associated XBeans (of which there may be zero, one, or many), because CascadeType.ALL means "apply persistence operations, including deletion, to any other entities accessible via this property or collection". If you didn't have CascadeType.ALL and you deleted a YBean that was referred to by one or more XBeans, then those XBeans would now referenced a non-existent YBean ID, so you'd probably need to do some cleanup in that case.
Both options are irrelevant if your business logic never deletes a YBean until it is not referred to by any XBeans, but if your business logic doesn't prevent the case, then you should cascade or not based on whether you want to get rid of the XBeans or whether you want to clean them up (but not delete them) to no longer refer to the YBean that's being deleted.
#ManyToOne
#JoinColumn(name="y_id")
private YBean yBean;
what is the column y_id ?
what is the definition of it?
you can try removing #JoinColumn(name="y_id") and let JPA handle it.
and also add fetch = FetchType.EAGER like this.
#OneToMany (mappedBy="yBean", cascade=CascadeType.ALL, fetch = FetchType.EAGER)
private List<XBean> xBeans;
Related
I created a field annotated with the #ReadOnlyProperty so I can track a computed field value. However, when I make a normal findAll query, I receive a SQL Error warning that this column (hasChildren) does not exist. I already tried removing the GET method, but it does not solve the problem at all. I also tried using the #Transient annotation but I could not save the value on my property.
#Entity
#Table
public class Parent extends BaseEntity {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
#OneToMany( fetch = FetchType.LAZY)
private List<Child> childs;
// Computed column that come from #Query annotation
#ReadOnlyProperty
private boolean hasChildren;
//Getters
//Setters
}
Try annotating the field with JPAs #Transient. This should tell it not to persist it in the database.
I am absolutly new in Hibernate development and I have the following problem.
I have 2 entity classes that maps 2 DB tables:
1) The first entity class (the main one) is named KM_ProjectInfo and map a DB table named KM_PROJECT.
2) The second entity class is named KM_ProjectInfoStatus and map a DB table named KM_PROJECT_INFO_STATUS.
So the second one represent a specific field of the first one (a status of the row representd by an instance of the KM_ProjectInfo class). Infact I have something like this:
1) KM_ProjectInfo class:
#Entity
#Table(name = "KM_PROJECT")
public class KM_ProjectInfo implements Serializable {
#Id
#GeneratedValue
private Long idProjectInfo;
#Column(name = "name")
private String name;
#Column(name = "technology")
private String technology;
#ManyToOne
#JoinColumn(name = "idCountry")
private KMCountry country;
#Column(name = "power")
private long power;
#Column(name = "cod")
private String cod;
#ManyToOne
#JoinColumn(name = "idProjectInfoStatus")
private KM_ProjectInfoStatus status;
// GETTERS & SETTERS
}
2) KM_ProjectInfoStatus:
#Entity
#Table(name = "KM_PROJECT_INFO_STATUS")
public class KM_ProjectInfoStatus implements Serializable {
#Id
#GeneratedValue
private Long idProjectInfoStatus;
#Column(name = "foldertech")
private Long foldertech;
#Column(name = "folderproject")
private Long folderproject;
// GETTERS & SETTERS
}
So, as you can see in the previous snippet, the KM_ProjectInfoStatuss is a field of the KM_ProjectInfo because I want that it contains the primary key of this table as foreign key.
In the logic of my application I want that at one row of the KM_PROJECT table (so at one instance of the KM_ProjectInfo entity class) is associated a single row of the KM_PROJECT_INFO_STATUS (one instance of the KM_ProjectInfoStatus entity class) because it represent a specific status for the KM_PROJECT row.
In my code I have:
#ManyToOne
#JoinColumn(name = "idProjectInfoStatus")
private KM_ProjectInfoStatus status;
but I think that is wrong because at one row of my first table it is associated a specific single row of the second table. But maybe I am missing something about how Hibernate work.
Can you help me to understand what I am missing? What it work? Why I have #ManyToOne instead #OneToOne?
Tnx
It all depends on how you want to model things. In terms of Database structure, OneToOne and ManyToOne are implemented in the same way:
One or more JoinColumns which makes a foreign key pointing to the primary key of the other table.
So both solutions correctly map to your database, but it depends if you want to allow several KM_ProjectInfo to point to the same KM_ProjectInfoStatus, or only allow a single one.
Note that, even though you would declare a OneToOne, you could still end up with multiple KM_ProjectInfo pointing to the same KM_ProjectInfoStatus if you don't manipulate Hibernate properly.
Here you did not declare the reverse relationship, but if you did, the declaration would have to be different:
In case of a OneToOne, you would have a KM_ProjectInfo member
In case of a OneToMany (reverse of ManyToOne), you would have a Collection<KM_ProjectInfo> member
From the description it seems you want to have one-to-one relationship. That is the project entity should have its very own status not shared by any other project. You could achieve this by using #OneToOne as below.
#Entity
#Table(name = "KM_PROJECT")
public class KM_ProjectInfo implements Serializable {
#Id
#GeneratedValue
private Long idProjectInfo;
#OneToOne
#JoinColumn(name = "idProjectInfoStatus")
private KM_ProjectInfoStatus status;
}
#Entity
#Table(name = "KM_PROJECT_INFO_STATUS")
public class KM_ProjectInfoStatus implements Serializable {
#Id
#GeneratedValue
private Long idProjectInfoStatus;
#OneToOne(mappedBy="idProjectInfoStatus")
private KM_ProjectInfo project;
}
This way you can have specific status for the KM_PROJECT.
Coming back to #ManyToOne, you will want to have this if you want to share the same status with multiple projects, but that's not what you want in your case. I have tried to explain mappings in simple way here One-to-One mapping.
I have an Evaluation entity that has an associated list of EvaluationEvaluator. I need to explicitly create that entity because it required an extra column "STATUS". Before I continue evaluation. I do: evaluation.setEvaluationEvaluator(listEvaluator) where listEvaluator is a list of EvaluationEvaluator type. Then persist(evaluation). When I run this, it does not throw any kind of exception. But in the database, it inserts in the Evaluation table, and not inserted into the EvaluationEvaluator table.
Below my Evaluation entity.
#Entity
public class Evaluation implements Serializable{
#Id
#GeneratedValue
private Long id;
//MORE FIELDS
#OneToMany(mappedBy="evaluation")
private List<EvaluationEvaluator> evaluators;
//CONSTRUCTORS
//GETTER AND SETTERS
}
This is my EvalutionEvaluator Entity:
#Entity
#Table(name= "EVALUATION_EVALUATOR")
#IdClass(EvaluationEvaluatorId.class)
public class EvaluationEvaluator implements Serializable{
#Id
#Column(name="EMPLOYEE_ID", insertable=false , updatable=false)
private Long EmployeeID;
#Id
#Column(name="EVALUATION_ID", insertable=false, updatable=false)
private Long EvaluationID;
#ManyToOne
#JoinColumn(name"EMPLOYEE_ID")
private Employee employee;
#ManyToOne
#JoinColumn(name"EVALUATION_ID")
private Evaluation evaluation;
#NotNull
private String status;
//CONSTRUCTORS
//GETTER AND SETTERS
}
This is my EvaluationEvaluatorId class
public class EvaluationEvaluatorId implements Serializable{
private Long employeeID;
private Long evaluationID;
//CONSTRUCTOR
//GETTER AND SETTERS
}
And finally, this is my EvaluationBean class
#Stateful
#Named
#LocalBean
#ConversationScoped
public class EvaluationBean {
#PersistentContext(type= PersistenceContextType.EXTENDED)
private EntityManager em;
#Inject
Conversation conversation;
private Evaluation evaluation;
//IN MY WEBPAGE I IMPLEMENT PRIMEFACES PICKLIST AND IT REQUIRE DUALIST TO HANDLE
private DualListModel<Employe> evaluators;
private EvaluationEvaluator evaluationEvaluator;
private List<EvaluationEvaluator> listEvaluators;
#Inject
private EmployeeList employeeList;
//GETTER AND SETTERS
public String begin(){
if (conversation.isTransient()){
converstaion.begin();
}
evaluationEvaluator = new EvaluationEvaluator();
listEvaluators = new ArrayList<EvaluationEvaluator>();
evaluation = new Evaluation();
List<Employee> source = employeeList.findAll();
target = new ArrayList<Employee>();
evaluators = new DualListModel<Employee>(source, target);
return "/evalution/evaluationAsig.xhtml"
}
public String save(){
Iterator<Employee> iterator = evaluators.getTarget().iterator();
while (iterator.hasNext()){
EvaluationEvaluator ev = new EvaluationEvaluator();
ev.setEmployee(iterator.next());
listEvaluators.add(ev);
}
evalution.setEvaluationEvaluators(listEvaluators);
if(evaluation.getId()==null){
em.persist(evalution);
} else{
em.merge(evalution);
}
if(!conversation.isTransient()){
convesation.end();
}
return "/evalution/evaluationsAsig.xhtml"
}
}
When I debug my application,apparently everything is correct, but I mentioned above, doesn't persist in EvaluationEvaluator table.
Your #OneToMany association is missing cascading configuration.
Add cascade = CascadeType.ALL or cascade = {CascadeType.PERSIST, CascadeType.MERGE} to the #OneToMany annotation. JPA assumes no cascading by default so you would need to persist each EvaluationEvaluator by yourself explicitely otherwise.
UPDATE
There is another thing wrong with the code - the Ids of EvaluationEvaluators are never assigned. You have a complex key made of two Long columns. Both are marked not insertable nor updatable which tells to JPA that the id is going to be somehow generated on database level and it should not care about it. There is however no sequence configured explicitely in your entity (although it is not necessarily required) and also from your comment:
I did what you recommended but it throws the following exception. "A different object with same identifier was already associated with the session"
I assume that this is not the case and both id column values default to null or zero and are same for all EvaluationEvaluators you are trying to persist. If you'd like the database to generate the id for you automatically use #GeneratedValue - Configure JPA to let PostgreSQL generate the primary key value - here you can find explanation how to do this (the database part is database dependent, this is for PostgreSQL). The most common use case however, is to configure the sequence but let hibernate pick the next value, instructions here - Hibernate sequence on oracle, #GeneratedValue(strategy = GenerationType.AUTO)
I am getting started with Hibernate Search/Lucene using Spring Boot and Spring Data, but I am having an issue with the index not getting updated (Checked with Luke tool).
I have 3 classes in my domain. This is Datasheet, my root entity:
#Entity
#Indexed
public class Datasheet
{
#Id
#GeneratedValue()
private long m_id;
#Field(name="name")
private String m_name;
#Field(name="description")
private String m_description;
#IndexedEmbedded(prefix = "documents.")
#OneToMany(cascade = CascadeType.REMOVE)
private Set<DatasheetDocument> m_documents;
}
Then DatasheetDocument:
#Entity
public class DatasheetDocument
{
#Id
#GeneratedValue()
private long m_id;
private String m_originalFileName;
#Field(name="componentName")
private String m_componentName;
#IndexedEmbedded(prefix = "manufacturer.")
#ManyToOne
private Manufacturer m_manufacturer;
}
And finally Manufacturer:
#Entity
public class Manufacturer
{
#Id
#GeneratedValue()
private long m_id;
#Field(name="name", analyze = Analyze.NO)
private String m_name;
private String m_website;
}
When I explicitly call startAndWait() on the indexer (org.hibernate.search.MassIndexer), then everything is as expected in the index. It contains the fields name, description, documents.componentName and documents.manufacturer.name.
However, when I now do updates through my #RestController classes that call into Spring Data CrudRepository classes, the index only changes when changing a direct field of Datasheet (E.g. name or description). Changing something to the DatasheetDocument instances does not update the index. Any idea why this might be?
Note that I have tried to add backreferences to the parent. For DatasheetDocument:
#ManyToOne
#ContainedIn
private Datasheet m_datasheet;
And for Manufacturer:
#ManyToMany
#ContainedIn
private Set<DatasheetDocument> m_datasheetDocuments;
But that does not help.
I am using Spring boot 1.0.1 which includes Hibernate 4.3.1. I added Hibernate Search 4.5.1. I see that Lucense 3.6.2 gets added transitively as well.
You need the back references for sure. Without them and in particular without #ContainedIn there is no way for Search to know that it has to update the Datasheet index when the DatasheetDocument instance changes.
Have you added mappedBy to the one to many side?
#OneToMany(cascade = CascadeType.REMOVE, mappedBy="m_datasheet")
private Set<DatasheetDocument> m_documents;
Also, how to you update DatasheetDocument? Can you show the code? Either way, you will need to make the associations bi-directional to start with.
FullTextSession fullTextSession = Search.getFullTextSession(session);
fullTextSession.openSession()
Object customer = fullTextSession.load( Datasheet.class, datasheetDocument.getDatasheet.getId() );
fullTextSession.index(customer);
fullTextSession.flushIndex();
I have the following mapping:
#Entity
public class Satellite implements Serializable, Comparable<Satellite> {
#NotNull #Id
private long id;
.....
#OrderColumn
#OneToMany(mappedBy = "satellite", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private List<DataModel> dataModel;
}
and a child entity:
#Entity #IdClass(value=DataModelPK.class)
public class DataModel implements Serializable, Comparable<DataModel> {
private static final long serialVersionUID = -3416403014857250990L;
#Id
private int orbit; // related to reference orbit file
private int dataPerOrbit; // in Gbit
#ManyToOne #Id
private Satellite satellite;
}
originally, DataModel was an embeddable entity, but for a better control over the primary key and the underlying structure of the db, I switched to a more traditional model.
The point is, during the loading of the entity now it generate a stack overflow!! I think there is some cyclic loading between those two entities and it got stuck!
I'm thinking to revert everything back to what it was, but I wish to understand why it gives me this error.
You have #IdClass for DataModel specified to be DataModelPK.class but your #Id annotation is on an int field.
This is a problem, it may be causing you stackoverflow but I am not certain.
Update I now see the second #Id annotation so I stand corrected, I will investigate furtuer.