ORACLE查询外键关联表和列

select t1.table_name, 
       t2.table_name as "TABLE_NAME(R)", 
       t1.constraint_name, 
       t1.r_constraint_name as "CONSTRAINT_NAME(R)",
       a1.column_name, 
       a2.column_name as "COLUMN_NAME(R)"
from user_constraints t1, user_constraints t2, user_cons_columns a1, user_cons_columns a2 
where 
     t2.table_name = '表名称' and
      t1.r_constraint_name = t2.constraint_name and 
      t1.constraint_name = a1.constraint_name and 
      t1.r_constraint_name = a2.constraint_name