t_errorbook
bookid\t int(10) userid\t varchar(40)courseid \tvarchar(40)gradeid\t varchar(40)uanswer\t varchar(400)qusetionid\tvarchar(40)typeid\t varchar(40)
PK__Reference_6
FK_Reference_4
t_paper
t_type
typeid\t int(5) typename\tvarchar(20)score\t int(5)remark\t varchar(100)
t_course
courseid\t int(5) coursename\tvarchar(20)coursestate\tvarchar(2)
FK_Reference_5
FK_Reference_3
t_grade
gradeid\t varchar(5) pkgradename\tvarchar(20)courseid\t varchar(40)
t_user
t_question
FK_Reference_1
