分2步骤：

1.

select * from user_constraints e where e.table_name='xxx';

2.

select a.constraint_type,a.table_name,a.status, b.table_name,b.column_name,b.constraint_name from user_constraints a

inner join user_cons_columns b
on a.constraint_name = b.constraint_name

where a.r_constraint_name='xxxx'