Oracle obtient des clés étrangères sur la table

SELECT c.OWNER, a.TABLE_NAME, a.COLUMN_NAME, a.CONSTRAINT_NAME, 
       c.R_OWNER AS REF_OWNER, cpk.TABLE_NAME AS REF_TABLE, 
       cpk.CONSTRAINT_NAME AS REF_PK
FROM ALL_CONS_COLUMNS a 
JOIN ALL_CONSTRAINTS c ON a.OWNER = c.OWNER
    AND a.CONSTRAINT_NAME = c.CONSTRAINT_NAME
 JOIN ALL_CONSTRAINTS cpk ON c.R_OWNER = cpk.OWNER
    AND c.R_CONSTRAINT_NAME = cpk.CONSTRAINT_NAME
WHERE c.CONSTRAINT_TYPE = 'R' AND c.TABLE_NAME= 'table_name';
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