Hibernate Community • View topic - What is the most effective way to do a many-to-many query?

View unanswered posts | View active topics

Board index » Hibernate & Java Persistence » Hibernate Users

All times are UTC - 5 hours [ DST ]

What is the most effective way to do a many-to-many query?

Page 1 of 1

[ 2 posts ]

Previous topic | Next topic

Author

Message

asklxf

Post subject: What is the most effective way to do a many-to-many query?

Posted: Mon May 22, 2006 3:51 am

Newbie

Joined: Fri Feb 17, 2006 12:18 am
Posts: 11

hi, I want to know what is the most effective way to execute a many-to-many query?

for example, Student, Course and Student_Course entities, how to select courses belong to specified student?

I know "select course in (select ...)" but it may not the effictive way.

thx!

Top

Jens

Post subject:

Posted: Mon May 22, 2006 6:16 am

Newbie

Joined: Wed Dec 21, 2005 6:41 am
Posts: 2

In plain SQL:

Code:

select  c.* 
  from Course c, Student_Course sc, Student s
  where c.id = sc.course_id
    and sc.student_id = s.id
    and s.id = :id

The HQL would probably be (depending on your mappings):