Getting inconsistent datatypes error while fetching data from ref cursor into a nested table - oracle

Question

I'm getting an error while fetching data from ref cursor into a nested table. Here is what I'm doing.
Object and table types:
CREATE OR REPLACE TYPE obj_report_org IS OBJECT
(dummy1 VARCHAR2(50),
dummy2 VARCHAR2(50),
dummy3 VARCHAR2(50),
dummy4 NUMBER(10));
CREATE OR REPLACE TYPE tab_report_org IS TABLE OF obj_report_org;
Procedure:
CREATE OR REPLACE PROCEDURE areaReport_test(v_name1 VARCHAR2,
v_name2 VARCHAR2, tab_report_set OUT tab_report_org)
IS
str VARCHAR2(2000);
v_num NUMBER := 1;
recordset SYS_REFCURSOR;
lv_tab_report_set tab_report_org := tab_report_org();
BEGIN
str := ' SELECT tab2.dummy1 ,tab3.dummy2,tab2.dummy3,tab1.dummy4 '||
' FROM tab1,tab2, tab3, tab4'||
' WHERE <JOIN CONDITIONS>';
OPEN recordset FOR
str||' START WITH tab1.name = :name1'||
' CONNECT BY PRIOR tab1.id = tab1.parent_id'||
' UNION '||
str||' START WITH tab1.name = :name2'||
' CONNECT BY PRIOR tab1.id = tab1.parent_id'
USING v_name1,v_name2;
FETCH recordset BULK COLLECT into lv_tab_report_set;
CLOSE recordset;
tab_report_set := lv_tab_report_set;
END;
Then I have an anonymous block to call the procedure:
DECLARE
l_tab_report_set tab_report_org;
BEGIN
areaReport_test('PRASHANT',null,l_tab_report_set);
FOR i in 1 .. l_tab_report_set.count
LOOP
DBMS_OUTPUT.PUT_LINE(
l_tab_report_set(i).dummy1|| ' | ' ||
l_tab_report_set(i).dummy2|| ' | ' ||
l_tab_report_set(i).dummy3|| ' | ' ||
l_tab_report_set(i).dummy4|| );
END LOOP;
END;
After running the anonymous block, I'm get this error:
ORA-00932: inconsistent datatypes: expected - got -
ORA-06512: at "AREAREPORT_TEST", line 36
ORA-06512: at line 5
00932. 00000 - "inconsistent datatypes: expected %s got %s"
It seems we cannot bulk fetch data into nested table formed from a SQL object. While sequence of fields and datatypes in object match with select query.
Please advise.

Answer 1

I will start from the bottom:
FETCH recordset BULK COLLECT into lv_tab_report_set;
There is a recordset that you are fetching into table of objects. So, recordset should contain list of objects.
SELECT tab2.dummy1 ,tab3.dummy2,tab2.dummy3,tab1.dummy4...
It is a list of columns and not an object. Here is a list of objects:
select obj_report_org(tab2.dummy1 ,tab3.dummy2,tab2.dummy3,tab1.dummy4) ...
few remarks about code in general
When you use UNION instead of UNION ALL, Oracle would sort both results and eliminate duplicates (there is no other way to do that). So just think about if you really need UNION and remember that there is a price for that.
You UNION two datasets that looks like could be combined together
START WITH tab1.name in (:name1, :name2)
Continues after ORA-22950
You are implisitly ordering your elements, but how ORACLE knows how to sort them?
By dummy1 or dummy2 or ...?
You have to options:
do not use sorting
that basically means no DISTINCT, GROUP BY, ORDER BY and no UNION (you are OK with UNION ALL)
define sorting for your objects
Follow up about methods in ORACLE Types
Your oracle type could have additional methods, some of them are special, notice 'ORDER MEMBER FUNCTION' below (copy from the link):
<!-- language: pl/sql -->
CREATE OR REPLACE TYPE location_typ AS OBJECT (
building_no NUMBER,
city VARCHAR2(40),
ORDER MEMBER FUNCTION match (l location_typ) RETURN INTEGER
);
/
CREATE OR REPLACE TYPE BODY location_typ AS
ORDER MEMBER FUNCTION match (l location_typ) RETURN INTEGER IS
BEGIN
IF building_no < l.building_no THEN
RETURN -1; -- any negative number will do
ELSIF building_no > l.building_no THEN
RETURN 1; -- any positive number will do
ELSE
RETURN 0;
END IF;
END;
END;/

Answer 2

Its not a problem of fetch its kind of datatype mismatch. Opening cursors and fetching is correct what you have written.