trouvé !
c'est ce que je cherchais, merci à tous pour votre aide.
SELECT a.table_name, a.column_name, uc.table_name, uc.column_name
FROM all_cons_columns a
JOIN all_constraints c ON a.owner = c.owner
AND a.constraint_name = c.constraint_name
JOIN all_constraints c_pk ON c.r_owner = c_pk.owner
AND c.r_constraint_name = c_pk.constraint_name
join USER_CONS_COLUMNS uc on uc.constraint_name = c.r_constraint_name
WHERE C.R_OWNER = 'myschema'
