I have an Entity_A that has OneToMany relationship with Entity_B.
Entity_B has a flag which indicates whether it is active.
How can I select join entity A and only entity B if it is active?
JPA Query:Documention
SELECT DISTINCT entA FROM Entity_A entA JOIN FETCH entA.entityBSet as entB WHERE entB.active = true
Update
- try #where
#Entity
public class Entity_A {
#Id
#Column(name = "ID")
private Integer id;
#OneToMany(mappedBy = "entityA")
#Where("active = true")
private Set<Entity_B> entityBSet;
}
#Entity
public class Entity_B {
#Id
#Column(name = "ID")
private Integer id;
#Id
#Column(name = "ACTIVE")
private Integer active;
#ManyToOne
private Entity_A entityA;
}
Related
i'm kinda struggling mapping the following schema with hibernate
table_a (A1_ID,A2_ID) --> PK = (A1_ID, A2_ID)
table_b (A1_ID, A2_ID, B1_ID) --> PK =(A1_ID, A2_ID, B1_ID)
where table_b's A1_ID and A2_ID should be foreingkey referencing respective table_A's columns
There is a one-to-many from TABLE_A to TABLE_B where TABLE_B's primary key is partially shared with TABLE_A's primary key
What I've tried so far
#Data
#Entity
#Table(name = "table_a")
#IdClass(TableA.TableAKey.class)
public class TableA {
#Id
#Column(name = "A1_ID)
private String a1_id;
#Id
#Column(name = "A2_ID)
private String a2_id;
#OneToMany(mappedBy = "tableA",fetch = FetchType.EAGER, cascade = CascadeType.ALL)
private List<TableB> tableB;
#Data
static class TableAKey implements Serializable {
private String a1_id;
private String a2_id
}
}
**CHILD ENTITY**
#Data
#Entity
#Table(name = "table_b")
#IdClass(TableB.TableBKey.class)
public class TableB {
#Id
#Column(name = "B1_ID)
private String b1_id;
#Id
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumns({
#JoinColumn(name = "a1_id", insertable = false, updatable = false),
#JoinColumn(name = "a2_id", insertable = false, updatable = false)
)}
private TableA tableA;
#Column(name = "A1_ID)
private String a1_id;
#Column(name = "A2_ID)
private String a2_id;
#Data
static class TableAKey implements Serializable {
private String b1_id;
private TableA tableA;
}
}
I was expecting i could be able to do something like this:
TableA tableA = new TableA();
t.setA1_id("a1id");
t.setA2_id("a2id");
TableB tableB = new TableB();
tableB.setB1Id("b1Id");
tableA.setTableB(Arrays.asList(tableB));
tableARepository.save(tableA);
And the code above I was expecting to "magically" perform the following insert at DB
INSERT INTO table_A (A1_ID,A2_ID) VALUES ('a1id',a2id');
INSERT INTO table_B (A1_ID,A2_ID, B1_ID) VALUES ('a1id',a2id','b1id')
but instead i get a "the column index is out of range: n, number of columns n-1".
I also tried with some embeddedId approach, using referenceColumnName but nothing.
Am I doing something wrong in the mapping or in the object creation process?
The problem is a lot similar to the following
https://hibernate.atlassian.net/browse/HHH-14340
I have an issue trying to generate multiple relationship in JPA with three Entities.
Order
Product
Modifier
I have an Entity to handle the relationship many to many.
OrderProducts (order_id and product_id)
Contains the relationship of one order can have multiple products
OrderDetails (order_products_id and modifier_id)
Contains the id of the previous relationship Order-Products and the Id of the modifier which is a set of multiple values that can affect the price of the product.
Not quite sure how to handle this kind of relationship in JPA as I'm new to it.
You need a join entity with a composite key. You will need to research it further.
Your entities:
#Entity
#Table(name = "ordertable")
#Data
public class Order {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(mappedBy = "order")
#EqualsAndHashCode.Exclude
private Set<OrderProductModifier> products;
}
#Entity
#Table(name = "product")
#Data
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#EqualsAndHashCode.Exclude
private BigDecimal unitPrice;
}
#Entity
#Table(name = "modifier")
#Data
public class Modifier {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#EqualsAndHashCode.Exclude
private BigDecimal modifier;
}
And the entity that ties it all together will need to have the foreign keys for each of the above entities, as you have noted.
#Entity
#Table(name = "orderproductmodifier")
#Data
public class OrderProductModifier {
#EmbeddedId
private OrderProductModifierId id;
#MapsId("orderId")
#ManyToOne
#EqualsAndHashCode.Exclude
#ToString.Exclude
private Order order;
#MapsId("productId")
#ManyToOne
#EqualsAndHashCode.Exclude
private Product product;
#MapsId("modifierId")
#ManyToOne
#EqualsAndHashCode.Exclude
private Modifier modifier;
}
#SuppressWarnings("serial")
#Embeddable
#Data
public class OrderProductModifierId implements Serializable {
private Long orderId;
private Long productId;
private Long modifierId;
}
This is pretty simple to use:
private void run() {
EntityManagerFactory factory = Persistence.createEntityManagerFactory("UsersDB");
EntityManager em = factory.createEntityManager();
em.getTransaction().begin();
Product product = new Product();
product.setUnitPrice(BigDecimal.TEN);
em.persist(product);
Modifier modifier = new Modifier();
modifier.setModifier(new BigDecimal(".90"));
em.persist(modifier);
Order order = new Order();
em.persist(order);
OrderProductModifier opm = new OrderProductModifier();
opm.setId(new OrderProductModifierId());
opm.setOrder(order);
opm.setProduct(product);
opm.setModifier(modifier);
em.persist(opm);
em.getTransaction().commit();
em.clear();
Order o = em.createQuery("select o from Order o join fetch o.products where o.id = 1", Order.class).getSingleResult();
System.out.println("Order for " + o.getProducts());
System.out.println("Order cost " + o.getProducts().stream().map(p->p.getProduct().getUnitPrice().multiply(p.getModifier().getModifier()).doubleValue()).collect(Collectors.summingDouble(Double::doubleValue)));
}
The above query could be better, but that will give you something to work on.
I have 3 entities named Student, Course, and StudentCourse as follows
#Entity
#Table(name = "student")
public class Student {
#Id
#GeneratedValue
private Integer id;
private String fullName;
}
#Entity
#Table(name = "course")
public class Course {
#Id
#GeneratedValue
private Integer id;
private String courseName;
}
#Entity
#Table(name = "student_course")
public class StudeCourse {
#Id
#GeneratedValue
private Integer studentId;
private Integer courseId;
private String extraColumn;
}
Restrictions: There are a couple of restrictions
One student can have only one course or no course at all
An extra entity (StudentCourse) is required to hold the relation with primary key as studentId only
StudentCourse is required and hence cannot be skipped
Get Student with Course entity if there is one registered
Help required in some magical code to retrieve Course of Student if there is one assigned.
#Entity
#Table(name = "student")
public class Student {
#Id
#GeneratedValue
private Integer id;
private String fullName;
// this is not correct code but just what I want
#JoinEntity(entity=StudentCourse, column="courseId")
private Course course;
}
StudentCourse is required and hence cannot be skipped
Ok, lets work with that.
One student can have only one course or no course at all
Implies that there is a #OneToOne relationship between Student and StudentCourse.
With the given information, the following entity model will work:
#Entity
#Table(name = "student")
public class Student {
#Column(name = "id")
#Id
#GeneratedValue
private Integer id;
#Column(name = "full_name")
private String full_name;
#OneToOne
#PrimaryKeyJoinColumn
private StudentCourse studentCourse;
}
#Entity
#Table(name = "student_course")
public class StudentCourse {
#Column(name = "id")
#Id
#GeneratedValue
private Integer id;
#JoinColumn(name = "id", nullable = false, updatable = false)
#MapsId
#OneToOne
private Student student;
#JoinColumn(name = "course_id")
#ManyToOne
private Course course;
...
}
A quick review:
#OneToOne on the Student.studentCourse field signifies that for every Student, there can be only one StudentCourse, and no more.
#PrimaryKeyJoinColumn on the Student.studentCourse field signifies that the value of the primary key column for Student should be used as the foreign key for the related entity, that is, StudentCourse.
#OneToOne on the StudentCourse.student field signifies that for every StudentCourse, there can be only one Student.
#MapsId on the StudentCourse.student field signifies that the primary key column for StudentCourse should be used as the join column for the association.
To check if a student has a course assigned, simply check if student.getStudentCourse() != null and then get the assigned course as student.getStudentCourse().getCourse().
I have three tables each mapping to one of these entities. The 'assigned' table acts as the relationship between 'users' and 'roles' with a foreign key to each table. How would I map this on my entities so that I can get a Set of EntityRoles from the UserEntity? I can't quite figure out how to make this work. Is this even possible?
#Entity
#Table(name = "users")
public class UserEntity {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="user_id")
private long id;
#Column(name="user_username")
private String username;
#Column(name="user_password")
private String password;
#Column(name="user_email")
private String email;
//I want to be able to get a set of RoleEntities
#OneToMany(fetch = FetchType.LAZY, mappedBy = "id")
private Set<RoleEntity> roles;
}
#Entity
#Table(name = "assigned")
public class AssignedEntity implements Serializable {
#Id
//#Column(name = "assigned_role")
#ManyToOne(targetEntity = RoleEntity.class, fetch = FetchType.LAZY)
#JoinColumn(name = "fk_role")
private long roleId;
#Id
//#Column(name = "assigned_user")
#ManyToOne(targetEntity = UserEntity.class, fetch = FetchType.LAZY)
#JoinColumn(name = "fk_user")
private long userId;
}
#Entity
#Table(name = "roles")
public class RoleEntity implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="role_id")
#OneToOne(fetch = FetchType.LAZY, mappedBy="roleId")
private long id;
#Column(name="role_name")
private String name;
}
You are using an incorrect/inconvenient mapping. Always keep things as simply as possible.
#Entity
#Table(name = "users")
public class User {
#Id
#GeneratedValue
private Long id;
#ManyToMany(fetch = FetchType.LAZY)
private List<Role> roles;
}
#Entity
#Table(name = "roles")
public class Role {
#Id
private Long id;
#Column
private String name;
}
A persistent provider will create a (valid) join table for you. You can specify the name of the join table using #JoinTable annotation. Also you will need to think about auto generation values of id for the Role entity: the roles table is something like a reference data table. So, probably, you will need to hardcode the id values.
To get user roles (in the persistent context):
user.getRoles()
I want to build the following pseudo query
Select a From APDU a where a.group.id= :id
group is a field in APDU class of the type APDUGroup.class.
I just want to get a list of APDUs based on APDUGroup's id.
How do i do that using a standard JPA query?
UPDATE
Yes, I have tried the above query and tried other variations for hours before posting in S/O. Here is the generated SQL for the query above:
SELECT t1.ID, t1.status, t1.type, t1.modified, t1.response, t1.expectedSize, t1.created, t1.description, t1.sequence, t1.name, t1.command, t1.recurring, t1.auth, t1.createdBy, t1.APDUGroup, t1.modifiedBy FROM APDUGroup t0, APDU t1 WHERE ((t0.ID = ?) AND (t0.ID = t1.APDUGroup))
The query looks okay but nothing get selected from my table.
There are at least 100 APDUs with APDUGroup = 1 in my test database.
I'm using eclipselink as the JPA provider.
Given the following Entities:
#Entity
public class APDU implements Serializable {
#Id
#GeneratedValue
private Long id;
#ManyToOne
private APDUGroup group;
//...
}
#Entity
public class APDUGroup implements Serializable {
#Id
#GeneratedValue
private Long id;
//...
}
The following query will return a list of APDUs for a given APDUGroup id:
select a from APDU a where a.group.id = :id
Oh, wait, that's your query :)
Entity 1:
#Entity
#Getter
#Setter
#Table(name = "invoices")
public class Invoice implements Serializable {
#Id
#GeneratedValue
#Column(name = "invoice_id", updatable = false, nullable = false)
private Long invoiceId;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "person_id", referencedColumnName = "person_id", insertable = false, updatable = false, nullable = false)
private Person person;
//...
}
Entity 2:
#Entity
#Getter
#Setter
#Table(name = "people")
public class Person implements Serializable {
#Id
#GeneratedValue
#Column(name = "person_id", updatable = false, nullable = false)
private Long personId;
//...
}
Finally, Your Data Access Object (JPA Repository)
#Repository
public interface InvoiceRepository extends JpaRepository<Invoice, Long> {
#Query(value="SELECT x FROM Invoice x WHERE x.person.personId = :myPersonId")
List<Invoice> findInvoiceByPersonId (long myPersonId);
}
I hope this example has been helpful :)