学生成绩管理系统源代码if exists(select 1 from sys.sysforeignkey where role='FK_CHOOSE_C_CHOOSE_CO_COURSES') then alter table choose_course delete foreign key FK_CHOOSE_C_CHOOSE_CO_COURSES end if; if exists(select 1 from sys.sysforeignkey where role='FK_CHOOSE_C_CHOOSE_CO_STUDENT') then alter ta
