QuerybyExample using parent object with other entity objects

fionac · **Joined:** Fri Jan 27, 2006 1:18 pm **Posts:** 1

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Hibernate version: 3.1

I want to search an entity object that has other entity objects as children (In a one to many relationship). Below is an example of what I more of less have. Since the search will have multi-criteria, it made sense for me to use the qbe.

Code:

public class Parent implements Serializable
{
    private Integer id;
    private String name;
    private List addresses; 
    private List children; (of type Child)
    ...
}

public class Child
{
     private Integer id;
     private String name; 
     ...
}

For searching the method looks something like this.
public Collection search(Parent parent, Child child) 
{

     Example example = Example.create(parent)
                                 .ignoreCase()
                                 .excludeZeroes()
                                 .excludeProperty("doNotUse")
                                 .enableLike(MatchMode.ANYWHERE);
     session = sessionFactory.openSession();
     
     return session.createCriteria(c).add(example)
                     .createCriteria("children")
                     .add( Example.create( child) )
                     .list();
... sessionFactory.session.close();
}

Error: hibernate error:org.hibernate.QueryException: could not resolve property: children of: com....Parent

Question: The error makes sense, but how can I add criteria to the query so that for example I'm able to list all parents that have a child with the name x, and so on for all of the other parent properties.
I read the documentation but I'm still confused as to how to reference the children.

Please advice.

gjlloyd · **Joined:** Sun Jun 06, 2004 10:13 am **Posts:** 20

i'm having a simliar issue using the Example class, can anyone offer any adivce here? this seems like an excellent way to query, but i can't find many examples using collections of child objects.

please advise.

baganokodo · **Joined:** Mon Jan 23, 2006 11:08 am **Posts:** 5

We had the same issue on one to many relations.

baganokodo · **Joined:** Mon Jan 23, 2006 11:08 am **Posts:** 5

We did QBE on one-to-many relationships through sub criteria query, like this,

Criteria subCriteria = providerCriteria.createCriteria("providerNames", JoinFragment.INNER_JOIN);
Disjunction disjunction = Expression.disjunction(); // "or"
Iterator itr = exampleProvider.getProviderNames().iterator();
while(itr.hasNext())
{
disjunction.add(Example.create((ProviderName)itr.next()).ignoreCase().excludeNone());
}
subCriteria.add(disjunction);

To make it work, we have to make sure the @hibernate.key defined inside @hibernate.set is nullable!!!