Storing XML using XSU, object VIEW and INSTEAD OF trigger

Question

Here is the point:
I've got 2 tables which are linked:
CREATE TABLE dept (
deptno NUMBER PRIMARY KEY,
deptname VARCHAR2(20)
CREATE TABLE emp (
empno NUMBER PRIMARY KEY,
empname VARCHAR2(20),
deptno NUMBER REFERENCES dept(deptno)
I've got the following message, which I want to insert in the tables using XSU (I already have a PL/SQL stored procedure which work perfectly for insertion into 1 table, using DBMS_XMLSave.insertXML or xmlgen.insertXML):
<DEPT>
<DEPTNO>10</DEPTNO>
<DEPTNAME>IT</DEPTNAME>
<EMP>
     <EMPNO>1</EMPNO>
     <EMPNAME>John</EMPNAME>
</EMP>
<EMP>
     <EMPNO>1</EMPNO>
     <EMPNAME>Phil</EMPNAME>
</EMP>
</DEPT>
So I've created the following object:
CREATE TYPE emp_t AS OBJECT
empno NUMBER,
empname VARCHAR2(20)
CREATE TYPE emplist_t AS TABLE OF emp_t;
CREATE TYPE dept_t AS OBJECT
deptno NUMBER,
deptname VARCHAR2(20),
emplist emplist_t
Now I understand that I should create an object VIEW and an INSTEAD OF trigger (That's what I read many times),
but I don't know how to structure the view and the trigger.
Could you help? (Example of a similar context, piece of code)
Thanks a lot
Marion

Answer 1

Hi John,
I have exactly the same issue as you experienced back in January. I have a complex data modelling requirement which requires the need to pivot rows into columns using ROW_NUMBER() and PARTITION clauses. To hide the complexity from the middle tier, I have created a database view and appropriate INSTEAD OF triggers and mapped my EO to the view. I have overriden the lock() method on the EO implementation class (to avoid ORA-02014) and would like to try the same solution you used with the pl/sql call to lock the record.
My question is, how did you manage the release of the lock if the transaction was not rolled back or committed by your application i.e. if the user closed the browser for instance.
In my naivity, I would like to think that the BC4J framework would release any locks for the database session when it found the servlet session to be terminated however my concern is that the lock would persist and cause complications.
Any assistance greatly appreciated (if you would be willing to supply your lock() method and pl/sql procedure logic I would be even more grateful!).
Many thanks,
Dave
London