Lazy vs Eager Loading & N+1 Problem

    Question 1: DATA JPA - Default Fetch Types

    What is the default fetch type for `@ManyToOne` and `@OneToOne` relationships in JPA?

    Question 2: DATA JPA - Default Collection Fetching

    What is the default fetch type for `@OneToMany` and `@ManyToMany` associations?

    Question 3: DATA JPA - Code Snippet (Lazy Loading)

    What happens when accessing `department.getEmployees()` if `employees` is mapped as `LAZY`?

    @Entity
public class Department {
    @OneToMany(mappedBy = "department", fetch = FetchType.LAZY)
    private List<Employee> employees;
}

    Question 4: DATA JPA - LazyInitializationException

    When does a `LazyInitializationException` occur in JPA/Hibernate?

    Question 5: DATA JPA - Code Snippet (EAGER Loading)

    What will happen in the following mapping?

    @Entity
public class Employee {
    @ManyToOne(fetch = FetchType.EAGER)
    private Department department;
}

    Question 6: DATA JPA - N+1 Query Problem Definition

    What is the N+1 problem in JPA/Hibernate?

    Question 7: DATA JPA - Code Snippet (N+1 Example)

    What performance issue will occur here if `employees` is `LAZY`?

    List<Department> departments = departmentRepo.findAll();
for (Department dept : departments) {
    System.out.println(dept.getEmployees().size());
}

    Question 8: DATA JPA - Solving N+1 with Fetch Join

    Which query strategy can help avoid the N+1 problem?

    Question 9: DATA JPA - Code Snippet (Fetch Join Solution)

    What does the following repository method achieve?

    @Query("SELECT d FROM Department d JOIN FETCH d.employees")
List<Department> findAllWithEmployees();

    Question 10: DATA JPA - Best Practices for Fetch Strategies

    Which of the following is considered the best practice in designing fetch strategies?