通过子表查父表，通过父表查子表

两上表student 和 teacher 其中，student表外键约束依赖于teacher表

情形一：已知student 表，如何找到student的父表?

 

select table_name from user_constraints where constraint_name = (select r_constraint_name from user_constraints where table_name = 'STUDENT' and constraint_type = 'R')

情形二：已知teacher表，如何找到teacher的子表？

 

select table_name from user_constraints where r_constraint_name = (select constraint_name from user_constraints where table_name = 'TEACHER' and constraint_type = 'P')