I have two table A and B
Table A:
ID_A
name
table B
ID_B
name
I joined both by a third table C table with their primary key
table C
ID_C
ID_A
ID_B
I'd like to know this relationship in jpa mapping to retrieve the list of object B inside object A
thank you,
Class A has list of C objects.
class A{
#Id
private Long Id;
#Column(name = "name_a", length = 5)
private Strin name_a;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "a", fetch = FetchType.LAZY)
private List<C> cList;
}
class B{
#Id
private Long Id;
#Column(name = "name_b", length = 5)
private String name_b;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "b", fetch = FetchType.LAZY)
private List<C> cList;
}
This is join table.Class C has A object and B object.
class C{
#Id
private Long id;
#JoinColumn(name = "id_a", referencedColumnName = "id", nullable = false)
#ManyToOne(optional = false, fetch = FetchType.LAZY)
private A a;
#JoinColumn(name = "id_b", referencedColumnName = "id", nullable = false)
#ManyToOne(optional = false, fetch = FetchType.LAZY)
private B b;
}
I have find a good example here http://viralpatel.net/blogs/hibernate-many-to-many-annotation-mapping-tutorial/
Related
Hi i have these 2 basic entity mapping for postgresql db, and i have wrote criteria for
fetching all activated user which have same key it is showing this error
org.hibernate.QueryException: could not resolve property: key.id of: com.sar.dfsapp.modal.ActivatedUser
#Entity
#Table(name = "activated_user")
public class ActivatedUser implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false, length = 11)
private long id;
#ManyToOne
#JoinColumn(name = "key_id", nullable = false)
private Key key;
}
#Entity
#Table(name = "key")
public class Key implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false, length = 11)
private long id;
#Column(name = "key_code", nullable = false)
private String keyCode;
}
Below is my criteria i have tried.
Criteria c = getSession().createCriteria(ActivatedUser.class);
c.add(Restrictions.eq("key.id", id));
List<ActivatedUser> result = c.list();
try this :
Criteria c = getSession().createCriteria(ActivatedUser.class);
Criteria keyCriteria = criteria.createCriteria("key", CriteriaSpecification.INNER_JOIN);
keyCriteria.add(Restrictions.eq("id", id));
List<ActivatedUser> result = c.list();
it there the same error ?
hope somebaody can help me. I have two entities related OneToMany.
First:
#Entity
#Table(name = "repartos")
#XmlRootElement
public class Repartos implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Basic(optional = false)
#Column(name = "id")
private Integer id;
#Basic(optional = false)
#NotNull
#Column(name = "fecha")
#Temporal(TemporalType.DATE)
private Date fecha;
#OneToMany(cascade = {CascadeType.ALL}, mappedBy = "repartoId")
public List<RepartosDetalle> repartosDetalleList;
.....
And then the another one:
#Entity
#Table(name = "repartos_detalle")
#XmlRootElement
public class RepartosDetalle implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Basic(optional = false)
#Column(name = "id")
private Integer id;
#JoinColumn(name = "reparto_id", referencedColumnName = "id")
#ManyToOne(optional = false)
private Repartos repartoId;
#Column(name = "descargado")
#Convert(converter = BooleanOneZeroConverter.class)
private boolean descargado;
public RepartosDetalle() {
}
public RepartosDetalle(Repartos repartoId) {
this.repartoId = repartoId;
}
public Repartos getRepartoId() {
return repartoId;
}
public void setRepartoId(Repartos repartoId) {
this.repartoId = repartoId;
}
public boolean isDescargado() {
return descargado;
}
public void setDescargado(boolean descargado) {
this.descargado = descargado;
}
}
What I try to get is all the Repartos given a date and where they have al least one RepartosDetalle with the property descargado=TRUE.
I've been trying with the following query but I do't get any result.
#Override
public List<Repartos> buscarPorFechaDescargados(Date searchDate) {
Query q = em.createQuery("SELECT e FROM Repartos e "
+ "WHERE e.fecha = :searchDate"
+ " AND e.repartosDetalleList.descargado=TRUE");
q.setParameter("searchDate", searchDate);
return q.getResultList();
}
Is there a proper way to make this query using one of the collection's property value?
Thanks a lot and nice weekend.
Try to use JOIN operator on these 2 entities - Repartos and RepartosDetalle :
SELECT e FROM Repartos e JOIN RepartosDetalle d
WHERE e.fecha = :searchDate
AND d.descargado = TRUE
I have two table:
CREATE TABLE [LeTYPE](
[LeNAME] [varchar](100) NOT NULL,
[Le_DESC] [varchar](500) NULL,
[LeFOR] [varchar](50) NOT NULL,
CONSTRAINT [PK_LeTYPE] PRIMARY KEY CLUSTERED
(
[LeNAME] ASC
)
)
CREATE TABLE [Le](
[SN] [int] IDENTITY(1,1) NOT NULL,
[LeNAME_FK] [varchar](100) NOT NULL,
[Le_SN] [int] NULL,
[LOWERRANGE] [float] NOT NULL,
[UPPERRANGE] [float] NOT NULL,
[Le_DESC] [varchar](500) NULL,
[COLOR] [varchar](45) NULL,
CONSTRAINT [Le_pk] PRIMARY KEY CLUSTERED
(
[SN] ASC
))
GO
ALTER TABLE [Le] WITH CHECK ADD CONSTRAINT [FK_Le_LeTYPE] FOREIGN KEY([LeNAME_FK])
REFERENCES [LeTYPE] ([LeNAME])
ON UPDATE CASCADE
ON DELETE CASCADE
GO
ALTER TABLE [Le] CHECK CONSTRAINT [FK_Le_LeTYPE]
GO
One tuple in LETYPE will have many LE.
JPA Entity generated by netbeans:
public class Letype implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#Basic(optional = false)
#NotNull
#Size(min = 1, max = 100)
#Column(nullable = false, length = 100)
private String Lename;
#Size(max = 500)
#Column(name = "Le_DESC", length = 500)
private String LeDesc;
#Basic(optional = false)
#NotNull
#Size(min = 1, max = 50)
#Column(nullable = false, length = 50)
private String Lefor;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "LenameFk", fetch = FetchType.LAZY)
private List<Le> LeList;
}
public class Le implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Basic(optional = false)
#NotNull
#Column(nullable = false)
private Integer sn;
#Column(name = "Le_SN")
private Integer LeSn;
#Basic(optional = false)
#NotNull
#Column(nullable = false)
private double lowerrange;
#Basic(optional = false)
#NotNull
#Column(nullable = false)
private double upperrange;
#Size(max = 500)
#Column(name = "Le_DESC", length = 500)
private String LeDesc;
#Size(max = 45)
#Column(length = 45)
private String color;
#JoinColumn(name = "LeNAME_FK", referencedColumnName = "LeNAME", nullable = false)
#ManyToOne(optional = false, fetch = FetchType.LAZY)
private Letype LenameFk;
}
Now, What I wanted was if I add a LETYPE from JSF view I would like to add multiple LE also at the same time.
LETYPE
-LE1
-LE2
-LE3
Do I need to set LenameFk manually in Le entity since I am getting
*Cannot insert the value NULL into column 'LENAME_FK'*? Why won't it automatically take it from Le enityt?
Note this snippet of code:
public class Le implements Serializable {
...
#ManyToOne(optional = false, fetch = FetchType.LAZY)
private Letype LenameFk;
...
}
optional = false means any instance of this entity must participate the relation, so, the foreign key field can not be null.
Your right, You need to set LenameFk manually in Le entity.
In General , for Bi-directional one-to-many two way relation , Accessor method should like below and assume entities are Customer and Order and one-to-many relation b/w them.
Customer.java
public Collection<Order> getOrders() {
return Collections.unmodifiableCollection(orders);
}
public void addToOrders(Order value) {
if (!orders.contains(value)) {
orders.add(value);
value.setCustomer(this);
}
}
public void removeFromOrders(Order value) {
if (orders.remove(value)) {
value.setCustomer(null);
}
}
Order.java
public void setCustomer(Customer value) {
if (this.customer != value) {
if (this.customer != null) {
this.customer.removeFromOrders(this);
}
this.customer = value;
if (value != null) {
value.addToOrders(this);
}
}
}
public Customer getCustomer() {
return customer;
}
I`m using Eclipse RCP with EJB exposed like WebServices. My services beans looks like follows
#Override
#SuppressWarnings("unchecked")
public List<Author> listAll() {
final Query query = this.entityManager.createQuery("from Author");
final List<Author> authors = query.getResultList();
return authors;
}
The two entityes are:
#Entity
#Table(name = "books")
public class Book implements Serializable {
#Id
private int id;
private String title;
private String summary;
private String isbn;
#Column(name = "published")
private Date publishingDate;
#Column(name = "created")
private Date createdAt;
#Column(name = "updated")
private Date modifiedAt;
#ManyToMany
#JoinTable(
name = "book_authors",
joinColumns = #JoinColumn(name = "book_id", referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name = "author_id", referencedColumnName = "id"))
private List<Author> authors;
and
#Entity
#Table(name = "authors")
public class Author implements Serializable {
private static final long serialVersionUID = 1L;
#Id
private int id;
#Column(name = "first_name")
private String firstName;
#Column(name = "middle_name")
private String middleName;
#Column(name = "last_name")
private String lastName;
#Column(name = "created")
private Date createdAt;
#Column(name = "updated")
private Date modifiedAt;
#ManyToMany
#JoinTable(
name = "book_authors",
joinColumns = #JoinColumn(name = "author_id", referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name = "book_id", referencedColumnName = "id"))
private List<Book> books;
In my TestWSCLient i`m trying to do something like this
AuthorServiceBeanServiceLocator locator = new AuthorServiceBeanServiceLocator();
AuthorServiceBean service = locator.getAuthorServiceBeanPort();
Author[] authors = service.listAll();
for(Author a : authors){
System.out.println(a.getFirstName());
}
and I`m getting this error
{....//xml.apache.org/axis/}stackTrace:Marshalling Error: failed to lazily initialize a collection of role: ro.cgs.entities.Author.books, no session or session was closed
I`m mention that if I do not make the Many-To-Many relationship all works fine. Can anybody tell me what should I do to fix this problem ?
I use Hibernate for persistence.
Thanks.
I'm trying to do something with JPA that'll use a lot on a project but I'm stuck.
I have 2 entities + a kind of "glue" entity, I'll call them
ClassA
ClassB
Glue
I want to add a new ClassA with new Glues set in it's list, ClassB's already exist.
That would do something like :
ClassA 1 | Glue 1 1 | ClassB 1
ClassA 1 | Glue 1 2 | ClassB 2
ClassA 1 | Glue 1 3 | ClassB 3
ClassA 1 | Glue 1 4 | ClassB 4
So as said ClassA and all Glues are to be inserted, ClassA has a List with the new Glues to be inserted.
Here they are :
#Entity
public class ClassA implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
(...)
#OneToMany(cascade = CascadeType.ALL, mappedBy = "classA")
private List<Glue> glueList;
(...)
}
#Entity
public class ClassB implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
(...)
}
#Entity
public class Glue implements Serializable {
#EmbeddedId
protected GluePK gluePK;
#JoinColumn(name = "id_class_a", referencedColumnName = "id", nullable = false, insertable = false, updatable = false)
#ManyToOne(optional = false)
private ClassA classA;
#JoinColumn(name = "id_class_b", referencedColumnName = "id", nullable = false, insertable = false, updatable = false)
#ManyToOne(optional = false)
private ClassB classB;
(...)
}
#Embeddable
public class GluePK implements Serializable {
#Basic(optional = false)
#NotNull
#Column(name = "id_class_a", nullable = false)
private int idClassA;
#Basic(optional = false)
#NotNull
#Column(name = "id_class_b", nullable = false)
private int idClassB;
(...)
}
When I try to persist my ClassA I'm getting something like :
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException:
Cannot add or update a child row: a foreign key constraint fails (bdd.glue, CONSTRAINT constraint_name FOREIGN KEY (id_class_a) REFERENCES ClassA (id) ON DELETE NO ACTION ON UPDATE NO ACTION)
I understand that he complains that Glues dont have ClassA's reference set but I'd like him to fill it just then he persists ClassA.
Is this achievable?
If not what's the best way to do it?
I'd like to stay on JPA without any specific vendor tricks (I'm using eclipselink) but if some vendor can do it easily I'll go for it.
Thanks!
I would remove the EmbeddedId, use an IdClass instead and just add the #Id to the #ManyToOne mappings.
See,
http://en.wikibooks.org/wiki/Java_Persistence/Identity_and_Sequencing#JPA_2.0
Or maybe even give Glue an id of its own.
You could also remove the insertable = false, updatable = false from the #ManyToOne and move them to the EmbeddedId.