Updated content for multi-level record structure in PLSQL

Question

Hi All,
please help me
Need a FUNCTION which would take PERSON_id as the INPUT PARAMETER and RETURN the FULL DETAILS in a multi-level record structure in PLSQL.
CREATE TABLE people(
name VARCHAR2(5),
person_id number
INSERT INTO people(name,person_id) VALUES ('n1',1);
INSERT INTO people(name,person_id) VALUES ('n2',2);
INSERT INTO people(name,person_id) VALUES ('n3',3);
INSERT INTO people(name,person_id) VALUES ('n4',4);
INSERT INTO people(name,person_id) VALUES ('n5',5);
INSERT INTO people(name,person_id) VALUES ('n6',6);
A person can be assigned many tasks. Below,we can see person_id =1 has 2 tasks 10,20
CREATE TABLE tasks(
task_id number,              --->PK
task_name VARCHAR2(5),
person_id number          -->FK to People
INSERT INTO tasks(task_id,task_name,person_id) VALUES (10, 'cleaning',1);
INSERT INTO tasks(task_id,task_name,person_id) VALUES (20', 'washing',1);
INSERT INTO tasks(task_id,task_name,person_id) VALUES (30, 'sweeping',2);
INSERT INTO tasks(task_id,task_name,person_id) VALUES (40, 'ironing',3);
Each TASK has many ACTIVTIES as below. Below,we can see task_id =10 ---->3 ACTIVITIES of activity_id of 100,200,300
CREATE TABLE activities(
activity_id number,
activity_name VARCHAR2(50),
task_id number,              --->FK  to task table
INSERT INTO activities(activity_id,activity_name,task_id)VALUES (100, 'Clean home',10);
INSERT INTO activities(activity_id,activity_name,task_id)VALUES (200, 'Clean Garden',10);
INSERT INTO activities(activity_id,activity_name,task_id)VALUES (300, 'Clean clothes,10');
INSERT INTO activities(activity_id,activity_name,task_id)VALUES (400, 'Wash car',20);
Write a FUNCTION which would take PERSON_id as the INPUT PARAMETER and RETURN the FULL DETAILS in a multi-level record structure in PLSQL.
Meaning We would get
First ,person_details for a person-->next level is TASKS-->Activities_list in a NESTED RECORD SET
create or replace function person_details(person_id NUMBER)
RETURNs a
PERSON_DETAILS RECORD structure as shown below.A person -->Tasks--> all activities
record PERSON_DETAILS[1]
     person_id,
     name
     TASKS_DETAILS[1]          ---->2nd level
                 task_id[1],
           task_name[1]
               ACTIVITIES[1]----->3rd level
                    activity_id[1],
                    activity_name[1]     
                  ACTIVITIES[2]
                    activity_id[2],
                    activity_name[2]                    
               ACTIVITIES[3]
                    activity_id[3],
                    activity_name[3]
*(1)--Most important part is how do i DEFINE AND DECLARE the RESULT RECORD SET in my FUNCTION?
  (2)--HOW DO WE DYNAMICALLY ALOCATE MEMORY for the record structure based on the no. of rows by each SELECT?
   (3)Access the nested levels and FILL in the DATA in the above record seperately USING SELECT statements.
*/*SELECT 1 ---Find and fill Person*/*
*select person_id,name from people where person_id =1*
*-->From this SELECT fill the OUTER record PERSON_DETAILS[no. of records] -->person_id,name*
*/**SELECT 2 ---I want to FIND all TASKS for THE ABOVE PERSON and fill the next part */*
*select task_id,name from tasks where person_id = PERSON_DETAILS[1].person_id*
*We get three TASK_ids,*
*-->From this, HOW TO fill DATA for each TASK,how to  PERSON_DETAILS[1]->TASKS_DETAILS[1st record].task_id -->person_id,name*
*/**SELECT 3 ---I want to FIND all ACTIVITIES for THE ABOVE TASKS and fill the next part */*
*for EACH of the TASKS found,we need to LOOP and*
*select activity_id,name from activities where task_id = PERSON_DETAILS[1].-->TASKS_DETAILS[1st record]--->ACTIVITY_DETAILS[1].activity_id*
I have tried my best to explain with the tables and the relationships.I just hope its not confusing now.Edited by: user_7000011 on 01-Apr-2009 12:46

Answer 1

try this one.
Learned something new today.
CREATE TABLE temp_clob_tab(result CLOB);
CREATE or replace TYPE task_t AS OBJECT("@task_id"   NUMBER,
                            last_name        VARCHAR2(20),
                             activitylist     activity_tab
create or replace type activity_t as object("@activity_id" number, activity_name varchar2(20));
CREATE or replace  TYPE tasklist_t AS TABLE OF task_t;
create or replace type activity_tab as table of activity_t;
CREATE or replace TYPE people_t AS OBJECT("@people_id" NUMBER,
                             task_name  VARCHAR2(20),
                             task_t          tasklist_t
DECLARE
  qryCtx DBMS_XMLGEN.ctxHandle;
  result CLOB;
BEGIN
  DBMS_XMLGEN.setRowTag(qryCtx, NULL);
  qryCtx := DBMS_XMLGEN.newContext
    ('SELECT people_t(person_id,
                    name,
                    CAST(MULTISET
                           (SELECT e.task_id, e.task_name,cast(multiset
                                    (select activity_id,activity_name from activities a
                                        where a.task_id = e.task_id) as activity_tab)
                              FROM tasks e
                              WHERE e.person_id= d.person_id)
                         AS tasklist_t))
        AS peoplexml
        FROM people d
        where person_id = 1');
  -- now get the result
  result := DBMS_XMLGEN.getXML(qryCtx);
  INSERT INTO temp_clob_tab VALUES (result);
  -- close context
  DBMS_XMLGEN.closeContext(qryCtx);
END;
select * from          temp_clob_tab ;output
<?xml version="1.0"?>
<ROWSET>
<ROW>
  <PEOPLEXML people_id="1">
   <TASK_NAME>n1</TASK_NAME>
   <TASK_T>
    <TASK_T task_id="10">
     <LAST_NAME>cleaning</LAST_NAME>
     <ACTIVITYLIST>
      <ACTIVITY_T activity_id="100">
       <ACTIVITY_NAME>Clean home</ACTIVITY_NAME>
      </ACTIVITY_T>
      <ACTIVITY_T activity_id="200">
       <ACTIVITY_NAME>Clean Garden</ACTIVITY_NAME>
      </ACTIVITY_T>
      <ACTIVITY_T activity_id="300">
       <ACTIVITY_NAME>Clean clothes</ACTIVITY_NAME>
      </ACTIVITY_T>
     </ACTIVITYLIST>
    </TASK_T>
    <TASK_T task_id="20">
     <LAST_NAME>washing</LAST_NAME>
     <ACTIVITYLIST>
      <ACTIVITY_T activity_id="400">
       <ACTIVITY_NAME>Wash car</ACTIVITY_NAME>
      </ACTIVITY_T>
     </ACTIVITYLIST>
    </TASK_T>
   </TASK_T>
  </PEOPLEXML>
</ROW>
</ROWSET>