Hi,
I am trying to create a view which shows inheritence but cannot get this
right. I have provided the table and data to assist anyone kind enough to
help us plus details of what we are trying to achieve.
CREATE TABLE GLEN_TEST (
TYPE VARCHAR2 (10),
PARENT VARCHAR2 (10),
PROPERTY NUMBER);

INSERT INTO GLEN_TEST ( TYPE, PARENT, PROPERTY ) VALUES ( 'A', NULL, 1);
INSERT INTO GLEN_TEST ( TYPE, PARENT, PROPERTY ) VALUES ( 'A', NULL, 2);
INSERT INTO GLEN_TEST ( TYPE, PARENT, PROPERTY ) VALUES ( 'B', 'A', 3);
INSERT INTO GLEN_TEST ( TYPE, PARENT, PROPERTY ) VALUES ( 'B', 'A', 4);
INSERT INTO GLEN_TEST ( TYPE, PARENT, PROPERTY ) VALUES ( 'C', 'B', 5);
INSERT INTO GLEN_TEST ( TYPE, PARENT, PROPERTY ) VALUES ( 'D', 'B', 6);
COMMIT;

We can see that this is a simple child-parent relationship.

If we do a select * we would get the following result:
TYPE PARENT PROPERTY
------- ------ ----------
A null 1
A null 2
B A 3
B A 4
C B 5
D B 6

What we are trying to achieve would look like this:
TYPE PARENT PROPERTY
------ ------ ----------
A null 1
A null 2
B A 1
B A 2
B null 3
B null 4
C A 1
C A 2
C B 3
C B 4
C null 5
D A 1
D A 2
D B 3
D B 4
D null 6

What we are trying to achieve is for every type to show all it's inheritance
i.e. type B inherits from type A because A is it's parent so the properties
for type B are 3 and 4 plus the properties for type A which are 1 and 2.
Type C would have it's own properties (5) plus those from type B (3,4) which
is it's parent plus those of type A (1,2) which is B's parent.

I have tried using the connect by prior but with no success as the
inheritence could be n layers deep. If anyone out there likes a challenge
and can help - we would be extremely grateful.
Regards
Glen

"GlenT" <glen.turner (AT) bt (DOT) com> wrote

Sounds procedural to me. I suggest you produce a PL/SQL procedure to build
and populate a temporary table using the tree walking concepts you've
already cosnsidered.

"GlenT" <glen.turner (AT) bt (DOT) com> wrote

Use connect by query to autojoin table with itself. This is how I tested
it:

1 select ta.t, ta.parent, tb.property
2 from af_glen_test ta, af_glen_test tb
3 where ta.parent in (select t
4 from af_glen_test tc
5 connect by prior t = parent
6 start with t = tb.t)
7 union
8 select t, null, property
9* from af_glen_test
SQL> /

T PARENT PROPERTY
---------- ---------- ----------
A 1
A 2
B A 1
B A 2
B 3
B 4
C B 1
C B 2
C B 3
C B 4
C 5
D B 1
D B 2
D B 3
D B 4
D 6

Looks OK?