Has anyone worked with one-to-many relationships with "cascade" ? It works fine without cascade. However, with cascading, it fails to save new children (issuing sql "update" instead of "insert"). I've made it bi-directional as recommended, but no use.
I'd greatly appreciate it if anyone could spare the time to have a look. Thanx a lot in advance.
The relationship: Department has several Employees.
------------------------
The classes:
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public class Employee {
String id;
double salary;
Department dept;
// Constructors
// Setters, getters , equals, hashCode
}
public class Department {
String id;
Set employees;
// Constructors
// setters, getters, equals, hashCode
public void addEmployee(Employee e){
employees.add(e);
e.setDept(this); // bi-directional
}
}
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Mapping (bi-di relashionship, with "inverse=tue" and "cascade="all":
------------------------
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping SYSTEM "hibernate-mapping-2.0.dtd">
<hibernate-mapping package="test">
<class name="Employee" table="Employee">
<id name="id" column="id" type="string" >
<generator class="assigned"/>
</id>
<property name="salary" />
<many-to-one name="dept" class="Department" column="dept_id" />
</class>
<class name="Department" table="Dept">
<id name="id" column="id" type="string" >
<generator class="assigned"/>
</id>
<set name="employees" inverse="true" cascade="all">
<key column="dept_id"/>
<one-to-many class="Employee" />
</set>
</class>
</hibernate-mapping>
------------------------
Usage:
------------------------
public static void main(String[] args) throws Exception{
Connection con = DriverManager.getConnection(url, user, pass);
Configuration hcfg=new Configuration();
hcfg=hcfg.configure(new File("hcfg.xml"));
SessionFactory fact= hcfg.buildSessionFactory();
Session session = fact.openSession(con);
Department dept = new Department("d1");
Employee emp=new Employee("e1", 9000);
Employee emp2=new Employee("e2", 8900);
dept.addEmployee(emp);
dept.addEmployee(emp2);
// Note dept.addEmployee() sets the relationship for both ends
session.save(dept);
// *** Problem ***
// employees are not saved to database (hibernated issues "update"
// sql instead of insert). They're not saved even if you add:
session.save(emp); session.save(emp2);
session.flush();
}
Thanx again.
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