Restrictions don't work for createAlias

Question

Here is my problem:

I want to do something like this query via hibernate criteria

select employee.name, employee.surname, department.name, position.name, department_position.end_date 
    from employee, department_position, department, position 
    where employee.id = department_position.employee_id
        and department_position.department_id = department.id
        and department_position.position_id = position.id
    and department_position.end_date is null

I have class Employee mapped to employee table

public class Employee {
    private int id;
    private String name;
    private String surname;
    private Date startDate;
    private Date endDate;
    private Set<DepartmentPosition> positions;
}

and DepartmentPosition (with all setters and getters of course)

public class DepartmentPosition {
    private int id;
    private Department department;
    private Position position;
    private Employee employee;
    private Date startDate;
    private Date endDate;
}

And I'm using this criteria

session.createCriteria(Employee.class)
    .createAlias("Positions", "pos")
    .add(Restrictions.isNull("pos.EndDate"));

Only 1 employee in my db matches this query (and he has 1 position with null endDate), but in resulting list it is repeated 3 times (looks like because this employee has 3 positions total)

How can i fix this?

Thanks for your replies

Answer 1

use criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);

Answer 2

Try to use restriction like Restrictions.isNull("Employee.Position.EndDate") - you did not specified in Restriction that Position is a property of Employee.

Answer 3

You should create the criteria on positions object then use projection to get the employee.

Criteria criteria = session.createCriteria(DepartmentPosition.class)
    .add(Restrictions.isNull("endDate"));

ProjectionList projList = Projections.projectionList();
projList.add(Projections.distinct(Projections.property("employee")));
criteria.setProjection(projList);