This example shows how to use JPQL keyword MEMBER OF to determine whether a value is an element of a collection. The value and the collection members must have the same type.
Quick Example
Query query = em.createQuery("SELECT e FROM Employee e where '222-222-222' MEMBER OF e.phoneNumbers");
List<Employee> resultList = query.getResultList();
Complete Example
Entities
@Entity
public class Employee {
@Id
@GeneratedValue
private long id;
private String name;
@ManyToMany(cascade = CascadeType.ALL)
private List<Task> tasks;
@ElementCollection
private List<String> phoneNumbers;
.............
}
@Entity
public class Task {
@Id
@GeneratedValue
private long id;
private String description;
private String supervisor;
.............
}
Using MEMBER OF
public class ExampleMain {
private static EntityManagerFactory entityManagerFactory =
Persistence.createEntityManagerFactory("example-unit");
public static void main(String[] args) {
try {
persistEmployees();
findEmployeeByPhoneNumber();
//with NOT and using parameter
findEmployeeByPhoneNumber2();
//using another entity instance with MEMBER OF
findEmployeeWithTask();
} finally {
entityManagerFactory.close();
}
}
public static void persistEmployees() {
Task task1 = new Task("Coding", "Denise");
Task task2 = new Task("Refactoring", "Rose");
Task task3 = new Task("Designing", "Denise");
Task task4 = new Task("Documentation", null);
Employee employee1 = Employee.create("Diana", Arrays.asList("111-111-111", "222-222-222"), task1);
Employee employee2 = Employee.create("Mike", Arrays.asList("666-666-666", "444-444-444"), task2, task3);
Employee employee3 = Employee.create("Tim", Arrays.asList("555-555-555", "222-222-222"), task2);
Employee employee4 = Employee.create("Jack", Arrays.asList("333-333-333"), task4);
EntityManager em = entityManagerFactory.createEntityManager();
em.getTransaction().begin();
em.persist(employee1);
em.persist(employee2);
em.persist(employee3);
em.persist(employee4);
em.getTransaction().commit();
em.close();
System.out.println("-- Employee persisted --");
System.out.println(employee1);
System.out.println(employee2);
System.out.println(employee3);
System.out.println(employee4);
}
private static void findEmployeeByPhoneNumber() {
System.out.println("-- Employees with phone number 222-222-222 --");
EntityManager em = entityManagerFactory.createEntityManager();
Query query = em.createQuery("SELECT e FROM Employee e where '222-222-222' MEMBER OF e.phoneNumbers");
List<Employee> resultList = query.getResultList();
resultList.forEach(System.out::println);
em.close();
}
private static void findEmployeeByPhoneNumber2() {
System.out.println("-- Employees with phone number NOT 222-222-222 --");
EntityManager em = entityManagerFactory.createEntityManager();
Query query = em.createQuery("SELECT e FROM Employee e where :theNumber NOT MEMBER OF e.phoneNumbers");
query.setParameter("theNumber", "222-222-222");
List<Employee> resultList = query.getResultList();
resultList.forEach(System.out::println);
em.close();
}
private static void findEmployeeWithTask() {
System.out.println("-- Employees with task 'Designing' --");
EntityManager em = entityManagerFactory.createEntityManager();
//find task by name first
Query query = em.createQuery("SELECT t FROM Task t where t.description LIKE 'Design%'");
List<Task> tasks = query.getResultList();
if(tasks.size()==0){
return;
}
Task theTask = tasks.get(0);
// using MEMBER OF
Query query2 = em.createQuery("SELECT e FROM Employee e where :requiredTask MEMBER OF e.tasks");
query2.setParameter("requiredTask", theTask);
List<Employee> resultList = query2.getResultList();
resultList.forEach(System.out::println);
//alternatively we can use JOIN
System.out.println("-- Employees with task 'Designing' using JOIN --");
Query query3 = em.createQuery("SELECT e FROM Employee e LEFT JOIN e.tasks t where "
+ "t.description LIKE 'Design%'");
List<Employee> resultList2 = query3.getResultList();
resultList2.forEach(System.out::println);
em.close();
}
} -- Employee persisted -- Employee{id=1, name='Diana', tasks=[Task{id=2, description='Coding', supervisor='Denise'}], phoneNumbers=[111-111-111, 222-222-222]} Employee{id=3, name='Mike', tasks=[Task{id=4, description='Refactoring', supervisor='Rose'}, Task{id=5, description='Designing', supervisor='Denise'}], phoneNumbers=[666-666-666, 444-444-444]} Employee{id=6, name='Tim', tasks=[Task{id=4, description='Refactoring', supervisor='Rose'}], phoneNumbers=[555-555-555, 222-222-222]} Employee{id=7, name='Jack', tasks=[Task{id=8, description='Documentation', supervisor='null'}], phoneNumbers=[333-333-333]} -- Employees with phone number 222-222-222 -- Employee{id=1, name='Diana', tasks=[Task{id=2, description='Coding', supervisor='Denise'}], phoneNumbers=[111-111-111, 222-222-222]} Employee{id=6, name='Tim', tasks=[Task{id=4, description='Refactoring', supervisor='Rose'}], phoneNumbers=[555-555-555, 222-222-222]} -- Employees with phone number NOT 222-222-222 -- Employee{id=3, name='Mike', tasks=[Task{id=4, description='Refactoring', supervisor='Rose'}, Task{id=5, description='Designing', supervisor='Denise'}], phoneNumbers=[666-666-666, 444-444-444]} Employee{id=7, name='Jack', tasks=[Task{id=8, description='Documentation', supervisor='null'}], phoneNumbers=[333-333-333]} -- Employees with task 'Designing' -- Employee{id=3, name='Mike', tasks=[Task{id=4, description='Refactoring', supervisor='Rose'}, Task{id=5, description='Designing', supervisor='Denise'}], phoneNumbers=[666-666-666, 444-444-444]} -- Employees with task 'Designing' using JOIN -- Employee{id=3, name='Mike', tasks=[Task{id=4, description='Refactoring', supervisor='Rose'}, Task{id=5, description='Designing', supervisor='Denise'}], phoneNumbers=[666-666-666, 444-444-444]}
Example ProjectDependencies and Technologies Used: - h2 1.4.197: H2 Database Engine.
- hibernate-core 5.2.13.Final: The core O/RM functionality as provided by Hibernate.
Implements javax.persistence:javax.persistence-api version 2.1 - JDK 1.8
- Maven 3.3.9
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