SQL recursion problem in custom groups table

Question

hi all,
Consider the following seemingly simple table structure ( with sample rows ) :
PERMISSION_ID P_ID DESCRIPTION DESIGNATION
============= ==== =========== =======
1776 Null Z-ENGINEERING 88888
1860 Null Z-LABORATORY 88888
1909 Null Z-RESEARCH 88888
1902 Null Z-PLANT 88888
1905 Null Z-SOFTWARE DESIGN 88888
1903 Null Z-BLANKET 88888
1904 Null Z-OFFICE 88888
40000 1909 James Gosling 67890
40001 1909 Edgar Codd 21135
40002 1904 Alan Turing 85542
40003 1909 Z-SOFTWARE DESIGN 88888
40004 1905 Dennis Ritchie 12111
40005 1909 Z-OFFICE 88888
40006 1776 Brian Kernighan 84251
40007 1904 Z-ENGINEERING 88888
Explanation of table structure :
(1) All rows with P_ID = {Null} are the root groups, and they all have a uniform DESIGNATION of 88888.
(2) All rows that starts with 40000 are memberships; under these memberships scheme, a root group can become a member of another root group, cascaded, which means that root groups can be members of another root group or they can be members of multiple root groups ( and cascaded even ), as long as the cascade do not end up in a circular reference, or an endless cycle. The idea here is so that the memberships for both groups and human members can be chained.
(3) Both root groups and human memberships are stored in the same table above, using rules (1) & (2) as the logic.
(4) No additional table may be added to this table in order to implement rules (1), (2), & (3); columns may be added, though.
(5) Use only plain SQL statements ( SELECT, CONNECT BY, PRIOR, NOCYCLES, etc ... ); PL/SQL, functions, and procedures are strongly discouraged.
Desired output of the query is as follows :
The SELECT query should return a list of all human members which belongs to a specific root group. Using the example table above, the initial query should have the following intended result set:
(start with p_id = 1909) -- 1909 is root group Z-RESEARCH
PERMISSION MEMBERS
========== =======
40000 James Gosling
40001 Edgar Codd
40003 Z-SOFTWARE DESIGN
40005 Z-OFFICE
However, Z-SOFTWARE DESIGN has it's own member , Dennis Ritchie, so the updated result set should be :
PERMISSION MEMBERS
========== =======
40000 James Gosling
40001 Edgar Codd
40004 Dennis Ritche
40005 Z-OFFICE
Same is true for Z-OFFICE, but it's member is another root group, Z-ENGINEERING, whose member is Brian Kernighan, thus the final result set list would be as follows, which is the final intended list :
PERMISSION MEMBERS
========== =======
40000 James Gosling
40001 Edgar Codd
40004 Dennis Ritche
40002 Alan Turing
40006 Brian Kernighan
The problem now would be, how to generate the final intended list using the table scheme illustrated above, with no additional tables, but possible additional columns, using Oracle's SELECT ... START WITH ... CONNECT BY PRIOR ?
Any theoretical advice is greatly appreciated; even our consulting firm cannot solve this problem. Coming here to the Oracle Forums itself is a last resort. Perhaps someone here can take a gander at this seemingly simple problem. Fact is, solving this problem has lots of applications, one of which is the ability to mimic Outlook's nested distribution groups list.
Thank you so much for your time.

Answer 1

Ok, first time back at a database, here my 2 cent.
I use the with-clause to simulate your sample-data, i have also added the master-reference-column i suggested. Just restrict the result to the group you want to. (i only put the id's in the query)
WITH DATA AS (SELECT 1776 PERMISSION_ID, TO_NUMBER(NULL) P_ID, TO_NUMBER(NULL) MASTER_PERMISSION_ID, 'Z-ENGINEERING' DESCRIPTION,  88888 DESIGNATION FROM DUAL
              UNION ALL
              SELECT 1860, Null, Null, 'Z-LABORATORY', 88888 FROM DUAL
              UNION ALL
              SELECT 1909, Null, Null, 'Z-RESEARCH', 88888 FROM DUAL
              UNION ALL
              SELECT 1902, Null, Null, 'Z-PLANT' ,88888 FROM DUAL
              UNION ALL
              SELECT 1905, Null, Null, 'Z-SOFTWARE DESIGN', 88888 FROM DUAL
              UNION ALL
              SELECT 1903, Null, Null, 'Z-BLANKET', 88888 FROM DUAL
              UNION ALL
              SELECT 1904, Null, Null, 'Z-OFFICE', 88888 FROM DUAL
              UNION ALL
              SELECT 40000, 1909, Null, 'James Gosling', 67890 FROM DUAL
              UNION ALL
              SELECT 40001, 1909, Null, 'Edgar Codd', 21135  FROM DUAL
              UNION ALL
              SELECT 40002, 1904, Null, 'Alan Turing', 85542 FROM DUAL
              UNION ALL
              SELECT 40003, 1909, 1905, 'Z-SOFTWARE DESIGN', 88888 FROM DUAL
              UNION ALL
              SELECT 40004, 1905, Null, 'Dennis Ritchie', 12111 FROM DUAL
              UNION ALL
              SELECT 40005, 1909, 1904, 'Z-OFFICE', 88888 FROM DUAL
              UNION ALL
              SELECT 40006, 1776, Null, 'Brian Kernighan', 84251  FROM DUAL
              UNION ALL
              SELECT 40007, 1904, 1776, 'Z-ENGINEERING', 88888  FROM DUAL
SELECT GROUP_REFERENCE,
       THE_USERS.PERMISSION_ID,
       USER_NAME,
       FROM_GROUP
  FROM (SELECT PERMISSION_ID,
               DESCRIPTION FROM_GROUP,
               CONNECT_BY_ROOT(PERMISSION_ID) GROUP_REFERENCE
          FROM (SELECT PERMISSION_ID, TO_NUMBER(NULL) P_MASTER, DESCRIPTION
                  FROM DATA
                 WHERE DESIGNATION=88888
                   AND P_ID IS NULL
                UNION ALL
                SELECT MASTER_PERMISSION_ID PERMISSION_ID,  P_ID P_MASTER, DESCRIPTION
                  FROM DATA
                 WHERE DESIGNATION=88888
                   AND P_ID IS NOT NULL       
        CONNECT BY PRIOR PERMISSION_ID=P_MASTER
        START WITH P_MASTER IS NULL
       ) THE_GROUPS,
       (SELECT P_ID PERMISSION_REFERENCE,
               PERMISSION_ID,
               DESCRIPTION USER_NAME
          FROM DATA
         WHERE MASTER_PERMISSION_ID IS NULL
           AND P_ID IS NOT NULL
       ) THE_USERS
WHERE THE_GROUPS.PERMISSION_ID=THE_USERS.PERMISSION_REFERENCE