逻辑模型图

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