如何将包含另一个实体对象的实体对象持久化到数据库？

Question

I have a problem with my function which is supposed to save data to database, function creates a new object which includes other objects. I am able to save and fetch objects which contain only primitive data types and Strings to Database , so the database and system works in this case. I am using JavaEE and EntityManager (persist). Any help?

Answer 1

You can define a cascade type on the parent entity. Have a look on the Java EE tutorial ( http://docs.oracle.com/javaee/6/tutorial/doc/bnbqa.html#bnbqm )

see the principal below

@Entity
public class Customer {
    @OneToMany(cascade=CascadeType.ALL, mappedBy="customer")
    public Set<Order> getOrders() { 
        return orders; 
    }
    ...
}

@Entity
public class Order {
    @OneToOne
    Customer customer;
    ...
}