SQL - Criando associações entre campos (relação transitiva)

Bem, eu não posso dizer nada para ORACLE, mas você pode gerenciá-lo com CTE recursiva no servidor sql. Aqui está minha solução de exemplo, ela faz o que você pediu assumindo que você tem uma tabela que mapeia a relação muitos-para-muitos de uma tabela para si mesma

DECLARE @testData table (EntityID int, EntityName varchar(1))
DECLARE @EntityRelations table (EntityID1 int, EntityID2 int)

INSERT INTO @testData
SELECT 1, 'A'
UNION
SELECT 2, 'B'
UNION
SELECT 3, 'C'
UNION
SELECT 4, 'D'
UNION
SELECT 5, 'E'
UNION
SELECT 6, 'F'
UNION
SELECT 7, 'G'
UNION
SELECT 8, 'Y'
UNION
SELECT 9, 'Z'

INSERT INTO @EntityRelations
SELECT 1, 2
UNION
SELECT 9, 2
UNION
SELECT 8, 2
UNION
SELECT 2, 3
UNION
SELECT 2, 4
UNION
SELECT 4, 5
UNION
SELECT 6, 7;


WITH Affiliations (EntityID, Entity1Name, Entity2Name) AS
(
    SELECT r.EntityID1
          ,e.EntityName as Entity1Name
          ,e2.EntityName as Entity2Name
    FROM @EntityRelations r
        JOIN @testData e ON e.EntityID = r.EntityID1
        JOIN @testData e2 ON e2.EntityID = r.EntityID2

    UNION ALL

    SELECT r.EntityID1
          ,e.EntityName as Entity1Name
          ,e2.EntityName as Entity2Name
    FROM @EntityRelations r
        JOIN @testData e ON e.EntityID = r.EntityID1
        JOIN @testData e2 ON e2.EntityID = r.EntityID2
        JOIN Affiliations a ON a.EntityID = r.EntityID2
)

,AffiliationsReverse (EntityID, Entity1Name, Entity2Name) AS
(
    SELECT r.EntityID2
          ,e.EntityName as Entity1Name
          ,e2.EntityName as Entity2Name
    FROM @EntityRelations r
        JOIN @testData e ON e.EntityID = r.EntityID1
        JOIN @testData e2 ON e2.EntityID = r.EntityID2

    UNION ALL

    SELECT r.EntityID2
          ,e.EntityName as Entity1Name
          ,e2.EntityName as Entity2Name
    FROM @EntityRelations r
        JOIN @testData e ON e.EntityID = r.EntityID1
        JOIN @testData e2 ON e2.EntityID = r.EntityID2
        JOIN AffiliationsReverse a ON a.EntityID = r.EntityID1
)


SELECT DISTINCT EntityName
FROM
(
SELECT a.Entity1Name AS EntityName
FROM Affiliations a
    JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID

UNION

SELECT a.Entity2Name AS EntityName
FROM Affiliations a
    JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID

UNION

SELECT ar.Entity1Name AS EntityName
FROM Affiliations a
    JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID

UNION

SELECT ar.Entity2Name AS EntityName
FROM Affiliations a
    JOIN AffiliationsReverse ar ON ar.EntityID = a.EntityID


) s