使用休眠标准投影限制所选字段

Question

I have an HQL query, but it has many where conditions. So I decided to use Hibernate Criteria.

Here is my query:

select distinct u.employee.id,u.employee.name,u.employee.address.phone from user u.

I tried it using the Criteria Project.property. But it gives an error. Is it possible to write Hibernate Criteria for this query?

Answer 1

Criteria cr = session.createCriteria(User.class)
    .setProjection(Projections.projectionList()
      .add(Projections.property("employee.id"), "id")
      .add(Projections.property("employee.name"), "Name"));

  List<User> list = cr.list();

Few more examples.

Criteria cr = session.createCriteria(Employee.class);

// To get total row count.

cr.setProjection(Projections.rowCount());

// To get average of a property.

cr.setProjection(Projections.avg("salary"));

// To get distinct count of a property.

cr.setProjection(Projections.countDistinct("firstName"));

// To get maximum of a property.

cr.setProjection(Projections.max("salary"));

// To get minimum of a property.

cr.setProjection(Projections.min("salary"));

// To get sum of a property.

cr.setProjection(Projections.sum("salary"));

Answer 2

List<User> users = (List<User>) dbSession.createCriteria(User.class)
          .add(Restrictions.eq("nameOfFieldInUserClass", value))                
          .list();

"nameOfFieldInUserClass" is name of restriction field in User, not name of column in DB .

and for distinct you can use

setProjection(Projections.distinct(Projections.property("nameOfField")));