Question

I would like to write a JPA entity class that has a one to many relationship. I would like to avoid defining the relationship in the parent class to avoid the data to be loaded every time a reference is made for the object even when there is no need for the associated data. I have read that even with Lazy loading, the data can be loaded so i need to avoid that.

In the following example,

Customer table
------------------------
customerid, customerName
1           John
2           Bob

Order Table – customerId is a foreign key to Customer

orderId, customerId, orderDate
1        1           12MAY2012 
1        1           13MAY2012
1        2           16MAY2012   

JPA Entities

@Entity
public class Customer {

    // all Customer-related fields WITHOUT @OneToMany relationship with Order
}

@Entity
public class Order {

    String orderDate;

    @ManyToOne
    private Customer owner;
}

How would i retrieve data from the customer table based on a condition on the order table? For example, how can i say “Get me all customers who have made an order where the orderDate is between two dates?

Answer 1

using hbm.xml there are query only properties to achieve what you want

http://ayende.com/blog/4054/nhibernate-query-only-properties