How to DEREF a nested Table of REFs?

Question

Can someone provide an example of how to deference, DEREF, a nested table of refs? (i.e. in order to access the attributes of the objects whose references appear in the nested table)
I'm creating object views based on relational tables. One of my object views contains a nested table of refs which represents a FK relationship, (1:M).
We're running ORACLE 8.1.7
EXAMPLE DDL:
/* FORWARD DECLARATIONS SO THINGS COMPILE */
CREATE TYPE TEST_DAY_T AS OBJECT
CREATE TYPE TEST_SECTION_T AS OBJECT
/* COLLECTION TYPES */
CREATE OR REPLACE
TYPE TEST_SECTION_REFTAB_T AS TABLE OF REF TEST_SECTION_T
/* OBJECT TYPES */
CREATE OR REPLACE
TYPE TEST_DAY_T AS OBJECT
(TEST_ID NUMBER(12)
,TEST_DAY NUMBER(1)
,TEST_SECTIONS TEST_SECTION_REFTAB_T
CREATE OR REPLACE
TYPE TEST_SECTION_T AS OBJECT
(TEST_ID NUMBER(12)
,TEST_DAY NUMBER(1)
,SECTION_SEQ NUMBER(3)
,SECTION_NAME VARCHAR2(32)
/* TABLE DEFS */
CREATE TABLE test_day
test_id NUMBER(12) NOT NULL,
test_day NUMBER(1) NOT NULL
ALTER TABLE test_day
ADD CONSTRAINT test_day_pk PRIMARY KEY (test_id,test_day)
CREATE TABLE test_section
test_id NUMBER(12) NOT NULL,
test_day NUMBER(1) NOT NULL,
section_seq NUMBER(3) NOT NULL,
section_name VARCHAR2(32) NOT NULL
ALTER TABLE test_section
ADD CONSTRAINT test_section_pk PRIMARY KEY (test_id,test_day,section_seq)
ALTER TABLE test_section
ADD CONSTRAINT test_section_fk01 FOREIGN KEY (test_id,test_day)
REFERENCES TEST_DAY(test_id,test_day)
/* OBJECT VIEWS */
CREATE OR REPLACE VIEW v_test_section_obj
OF TEST_SECTION_T
WITH OBJECT OID (TEST_ID, TEST_DAY, SECTION_SEQ)
AS
SELECT TS.TEST_ID,
TS.TEST_DAY,
TS.SECTION_SEQ,
TS.SECTION_NAME
FROM TEST_SECTION TS
CREATE OR REPLACE VIEW v_test_day_obj
OF TEST_DAY_T
WITH OBJECT OID (TEST_ID, TEST_DAY)
AS
SELECT TD.TEST_ID,
TD.TEST_DAY,
CAST(MULTISET(SELECT ref(tso)
FROM v_test_section_obj tso
WHERE tso.test_id = td.test_id
AND tso.test_day = td.test_day) AS TEST_SECTION_REFTAB_T)
FROM TEST_DAY TD
/* CLEANUP */
DROP VIEW v_test_day_obj
DROP VIEW v_test_section_obj
DROP TYPE TEST_SECTION_REFTAB_T
DROP TYPE TEST_DAY_T
DROP TYPE TEST_SECTION_T
DROP TABLE TEST_SECTION
DROP TABLE TEST_DAY

Answer 1

Martin,
You can check out an example online at http://otn.oracle.com/docs/products/oracle9i/doc_library/release2/appdev.920/a96594/adobjvew.htm#436463.
Regards,
Geoff
Can someone provide an example of how to deference, DEREF, a nested table of refs? (i.e. in order to access the attributes of the objects whose references appear in the nested table)
I'm creating object views based on relational tables. One of my object views contains a nested table of refs which represents a FK relationship, (1:M).
We're running ORACLE 8.1.7
EXAMPLE DDL:
/* FORWARD DECLARATIONS SO THINGS COMPILE */
CREATE TYPE TEST_DAY_T AS OBJECT
CREATE TYPE TEST_SECTION_T AS OBJECT
/* COLLECTION TYPES */
CREATE OR REPLACE
TYPE TEST_SECTION_REFTAB_T AS TABLE OF REF TEST_SECTION_T
/* OBJECT TYPES */
CREATE OR REPLACE
TYPE TEST_DAY_T AS OBJECT
(TEST_ID NUMBER(12)
,TEST_DAY NUMBER(1)
,TEST_SECTIONS TEST_SECTION_REFTAB_T
CREATE OR REPLACE
TYPE TEST_SECTION_T AS OBJECT
(TEST_ID NUMBER(12)
,TEST_DAY NUMBER(1)
,SECTION_SEQ NUMBER(3)
,SECTION_NAME VARCHAR2(32)
/* TABLE DEFS */
CREATE TABLE test_day
test_id NUMBER(12) NOT NULL,
test_day NUMBER(1) NOT NULL
ALTER TABLE test_day
ADD CONSTRAINT test_day_pk PRIMARY KEY (test_id,test_day)
CREATE TABLE test_section
test_id NUMBER(12) NOT NULL,
test_day NUMBER(1) NOT NULL,
section_seq NUMBER(3) NOT NULL,
section_name VARCHAR2(32) NOT NULL
ALTER TABLE test_section
ADD CONSTRAINT test_section_pk PRIMARY KEY (test_id,test_day,section_seq)
ALTER TABLE test_section
ADD CONSTRAINT test_section_fk01 FOREIGN KEY (test_id,test_day)
REFERENCES TEST_DAY(test_id,test_day)
/* OBJECT VIEWS */
CREATE OR REPLACE VIEW v_test_section_obj
OF TEST_SECTION_T
WITH OBJECT OID (TEST_ID, TEST_DAY, SECTION_SEQ)
AS
SELECT TS.TEST_ID,
TS.TEST_DAY,
TS.SECTION_SEQ,
TS.SECTION_NAME
FROM TEST_SECTION TS
CREATE OR REPLACE VIEW v_test_day_obj
OF TEST_DAY_T
WITH OBJECT OID (TEST_ID, TEST_DAY)
AS
SELECT TD.TEST_ID,
TD.TEST_DAY,
CAST(MULTISET(SELECT ref(tso)
FROM v_test_section_obj tso
WHERE tso.test_id = td.test_id
AND tso.test_day = td.test_day) AS TEST_SECTION_REFTAB_T)
FROM TEST_DAY TD
/* CLEANUP */
DROP VIEW v_test_day_obj
DROP VIEW v_test_section_obj
DROP TYPE TEST_SECTION_REFTAB_T
DROP TYPE TEST_DAY_T
DROP TYPE TEST_SECTION_T
DROP TABLE TEST_SECTION
DROP TABLE TEST_DAY