alter table class
drop constraint FK_CLASS_SC_CL_REL_SCHOOL
go

alter table class
add constraint FK_CLASS_SC_CL_REL_SCHOOL foreign key (schno)
references school (schno)
go

alter table Depart
drop constraint FK_DEPART_TC_DP_REL_TEACHER
go

alter table Depart
add constraint FK_DEPART_TC_DP_REL_TEACHER foreign key (tno)
references teacher (tno)
go

alter table teacher
drop constraint FK_TEACHER_TC_DP_REL_DEPART
go

alter table teacher
add constraint FK_TEACHER_TC_DP_REL_DEPART foreign key (dno)
references Depart (dno)
go

alter table course
drop constraint FK_COURSE_教师授课_TEACHER
go

alter table course
add constraint FK_COURSE_教师授课_TEACHER foreign key (tno)
references teacher (tno)
go

alter table 教师派课单
drop constraint FK_教师派课单_教师派课单2_COURSE
go

alter table 教师派课单
add constraint FK_教师派课单_教师派课单2_COURSE foreign key (cno)
references course (cno)
go

alter table 教师派课单
drop constraint FK_教师派课单_教师派课单_TEACHER
go

alter table 教师派课单
add constraint FK_教师派课单_教师派课单_TEACHER foreign key (tno)
references teacher (tno)
go

alter table 教师派课单
drop constraint FK_教师派课单_教师派课单3_CLASS
go

alter table 教师派课单
add constraint FK_教师派课单_教师派课单3_CLASS foreign key (bno)
references class (bno)
go

alter table student
drop constraint FK_STUDENT_CL_ST_REL_CLASS
go

alter table student
add constraint FK_STUDENT_CL_ST_REL_CLASS foreign key (bno)
references class (bno)
go

alter table class
drop constraint FK_CLASS_DP_CL_REL_DEPART
go

alter table class
add constraint FK_CLASS_DP_CL_REL_DEPART foreign key (dno)
references Depart (dno)
go

alter table 考试
drop constraint FK_考试_考试2_STUDENT
go

alter table 考试
add constraint FK_考试_考试2_STUDENT foreign key (sno)
references student (sno)
go

alter table 考试
drop constraint FK_考试_考试_COURSE
go

alter table 考试
add constraint FK_考试_考试_COURSE foreign key (cno)
references course (cno)
go

alter table course
drop constraint FK_COURSE_CL_CS_REL_CLASS
go

alter table course
add constraint FK_COURSE_CL_CS_REL_CLASS foreign key (bno)
references class (bno)
go