oracle查看表之间主外键约束关系

select a.constraint_name, a.table_name, b.constraint_name 
from user_constraints a, user_constraints b 
where a.constraint_type = 'R' 
and b.constraint_type = 'P' 
and a.r_constraint_name = b.constraint_name  
and b.table_name='FG_ROOM'
P 代表主键 
R 代表外键