Hey Everyone,
I have a question about mapping inheritance.
What I'm having trouble doing is reading and updating a collection of a
subclasses. It writes the Manager entry with the Manager => Employee
mapping without problem. Unfortunately when I read in the Company class
and it loads a collection of employees it does not collect the Manager =>
Employee mapping. Based on the method of Inheritance I used I was under
the impression that OJB would use the class listed in ojbConcreteClass
(class_name) as the class to load the data into, and since that class in
some cases is a Manager, it should load and populate the Manager's
Collection of Employees.
Any help you can offer would be most appreciated. Thank!
The following is an EXAMPLE of what I'm trying to do.
Classes --- Based on documentation examples:
==================================
public class Company {
private Integer id;
private Collection<Employee> employees;
private String name;
public Company() { }
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Collection<Employee> getEmployees() {
if (employees == null)
employees = new ArrayList();
return employees;
}
public void setEmployees(Collection<Employee> employees) {
this.employees = employees;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
public class Employee {
protected Integer id;
protected Integer companyId;
protected String name;
protected String ojbConcreteClass;
public Employee() { this.ojbConcreteClass =
this.getClass().getName(); }
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getCompanyId() {
return companyId;
}
public void setCompanyId(Integer companyId) {
this.companyId = companyId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getOjbConcreteClass() {
return ojbConcreteClass;
}
public void setOjbConcreteClass(String ojbConcreteClass) {
this.ojbConcreteClass = ojbConcreteClass;
}
}
public class Manager extends Employee {
private Collection<Employee> employees;
public Manager() { super(); }
public Collection<Employee> getEmployees() {
if (employees == null)
employees = new ArrayList();
return employees;
}
public void setEmployees(Collection<Employee> employees) {
this.employees = employees;
}
}
Database(DB2) tables:
================
CREATE TABLE company (
company_id INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1
INCREMENT BY 1),
name varchar(255) NOT NULL,
--
PRIMARY KEY (company_id)
);
CREATE TABLE employee (
employee_id INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1
INCREMENT BY 1),
name varchar(255) NOT NULL,
company_id_FK INTEGER NOT NULL,
class_name varchar(255) NOT NULL,
--
PRIMARY KEY (employee_id),
FOREIGN KEY (company_id_FK) REFERENCES company (company_id)
);
CREATE TABLE manager_employee_map (
manager_id_FK INTEGER NOT NULL,
employee_id_FK INTEGER NOT NULL,
--
FOREIGN KEY (manager_id_FK) REFERENCES employee (employee_id),
FOREIGN KEY (employee_id_FK) REFERENCES employee (employee_id)
);
Repository mapping:
===============
<class-descriptor class="Company" table="COMPANY">
<field-descriptor name="id" column="COMPANY_ID"
jdbc-type="INTEGER"
primarykey="true" autoincrement="true" access="readonly"/>
<field-descriptor name="name" column="NAME" jdbc-type="VARCHAR" />
<collection-descriptor name="employees"
element-class-ref="Employee"
auto-delete="true" auto-update="true" auto-insert="true"
auto-retrieve="true">
<inverse-foreignkey field-ref="CompanyId"/>
</collection-descriptor>
</class-descriptor>
<class-descriptor class="Employee" table="employee">
<extent-class class-ref="Manager"/>
<field-descriptor name="id" column="EMPLOYEE_ID"
jdbc-type="INTEGER"
primarykey="true" autoincrement="true" access="readonly"/>
<field-descriptor name="name" column="NAME" jdbc-type="VARCHAR" />
<field-descriptor name="companyId" column="COMPANY_ID_FK"
jdbc-type="INTEGER"/>
<field-descriptor name="ojbConcreteClass" column="CLASS_NAME"
jdbc-type="VARCHAR" />
</class-descriptor>
<class-descriptor class="Manager" table="employee">
<field-descriptor name="id" column="EMPLOYEE_ID"
jdbc-type="INTEGER"
primarykey="true" autoincrement="true" access="readonly"/>
<field-descriptor name="name" column="NAME" jdbc-type="VARCHAR" />
<field-descriptor name="companyId" column="COMPANY_ID_FK"
jdbc-type="INTEGER"/>
<field-descriptor name="ojbConcreteClass" column="CLASS_NAME"
jdbc-type="VARCHAR" />
<collection-descriptor name="employees"
element-class-ref="Employee"
auto-retrieve="true" auto-update="true" auto-delete="true"
indirection-table="MANAGER_EMPLOYEE_MAP">
<fk-pointing-to-this-class column="MANAGER_ID_FK"/>
<fk-pointing-to-element-class column="EMPLOYEE_ID_FK"/>
</collection-descriptor>
</class-descriptor>
Adam Brons
