simple criteria question

sluramod · **Posted:** Thu Apr 27, 2006 3:10 pm

Hello,

I have a simple query:

Code:

select d.projects from Department d where d.id=1

where projects mapped as many-to-many association.

I want to do the same thing using Criteria API, i.e. retrieve list of projects from the association; not a map, just a list of projects.

Please help.

Alexei

bkmr_77 · **Joined:** Tue Apr 25, 2006 12:04 pm **Posts:** 260

Try this one.

Code:

DetachedCriteria dc = DetachedCriteria.forClass( Project.class , "p" )
                                    .createAlias( "departments", "depts" )
                                    .add( Restrictions.eq( "depts.id", new Integer(1) ) );
List r = dc.getExecutableCriteria( session ).list();

sluramod · **Posted:** Thu Apr 27, 2006 3:58 pm

That's not what the original query expressed.

I cannot navigate back from projects to departments (project does not have references to departments), so your solution won't work.

Alexei

neketsushonen · **Posted:** Thu Apr 27, 2006 4:30 pm

[quote="sluramod"]Hello,

I have a simple query:

[code]select d.projects from Department d where d.id=1[/code]

where projects mapped as many-to-many association.

I want to do the same thing using Criteria API, i.e. retrieve list of projects from the association; not a map, just a list of projects.

Please help.

Alexei[/quote]

The Reference Document of Hibernate sayed:

[quote]
You may also specify properties of components or composite user types (and of components of components, etc). Never try to use a path-expression that ends in a property of component type (as opposed to a property of a component). For example, if store.owner is an entity with a component address

store.owner.address.city // okay
store.owner.address // error!
[/quote]

So, u can´t get the List from a HQL senteces. You can do inversely, like this:
from Project p where p.department.id = 1

I guess that will help you to solve your problem.

Requests for comments.

bkmr_77 · **Joined:** Tue Apr 25, 2006 12:04 pm **Posts:** 260

The other way around

Code:

DetachedCriteria dc = DetachedCriteria.forClass( Department.class , "dept" )
                                    .createAlias( "projects", "projs" )
                                    .add( Restrictions.eq( "dept.id", new Integer(1) ) );
List r = dc.getExecutableCriteria( session ).list();

If there is navigation from Department to Projects then why use criteria or HQL query. Instead just loading the Department with its prim key will give you association to projects.

sluramod · **Posted:** Thu Apr 27, 2006 5:01 pm

Quote:

So, u can´t get the List from a HQL senteces. You can do inversely, like this:
from Project p where p.department.id = 1

FYI, select d.projects from Department d where d.id=1 works just fine.

Quote:

DetachedCriteria dc = DetachedCriteria.forClass( Department.class , "dept" )
.createAlias( "projects", "projs" )
.add( Restrictions.eq( "dept.id", new Integer(1) ) );
List r = dc.getExecutableCriteria( session ).list();

r contains list of departments in this case, so it is not a solution either.

I know that I can access list of Projects from Department, but I need criteria object for that query, not results of its execution.