設計表

通過設計經典的學生管理系統，熟悉數據庫的使用。以下是根據課程，成績，老師這幾者的關系設計表結構。

學生表：

Student	?	?	?	?
字段名	類型	是否為空	主鍵	描述
stdid	int	否	是	學生ID
stdname	varchar(100)	否		學生姓名
gender	enum('M', 'F')	是		性別
age	int	是		年齡

課程表：

Course	?	?	?	?
字段名	類型	是否為空	主鍵	描述
couid	int	否	是	課程ID
cname	varchar(50)	否		課程名字
tid	int	否		老師ID

成績表

字段名	類型	是否為空	主鍵	描述
sid	int	否	是	分數ID
stdid	int	否		學生id
couid	int	否		課程id
grade	int	否		分數

教師表：

Teacher	?	?	?	?
字段名	類型	是否為空	主鍵	描述
tid	int	否	是	老師ID
tname	varcher(100)	否		老師名字

?

?有了表結構，創建表

#!/usr/bin/env python #coding:utf8import MySQLdb def connect_mysql():db_config = {"host":"172.16.61.158","port":3306,"user":"root","passwd":"123456","db":"stu","charset":"utf8",}try:cnx = MySQLdb.connect(**db_config)except Exception as e :raise ereturn cnxstudent = '''create table student(stdid int not NULL ,stdname varchar(100) not null,gender enum('M','F'),age int);''' course = '''create table course(couid int not null,cname varchar(50) not null ,tid int not null );'''score = '''create table score(sid int not null,stdid int not null,couid int not null,grade int not null);'''teacher = '''create table teacher(tid int not null,tname varchar(100) not null );'''if __name__ == "__main__":cnx = connect_mysql()print(cnx)cus = cnx.cursor()try :print studentcus.execute(student)print coursecus.execute(course)print scorecus.execute(score)print teachercus.execute(teacher)cus.close()cnx.commit()except Exception as e :cnx.rollback()print("error,{0}".format(e))raise efinally:cnx.close()

執行結果：

<_mysql.connection open to '172.16.61.158' at 27b6e48> create table student(stdid int not NULL ,stdname varchar(100) not null,gender enum('M','F'),age int); create table course(couid int not null,cname varchar(50) not null ,tid int not null ); create table score(sid int not null,stdid int not null,couid int not null,grade int not null); create table teacher(tid int not null,tname varchar(100) not null );

?有了表，下步添加數據：

?

#!/usr/bin/env python #coding:utf8import MySQLdb def connect_mysql():db_config = {"host":"172.16.61.158","port":3306,"user":"root","passwd":"123456","db":"stu","charset":"utf8",}try:cnx = MySQLdb.connect(**db_config)except Exception as e :raise ereturn cnxstudent = '''set @i:= 10000; insert into student select @i:=@i +1,substr(concat(sha1(rand()),sha1(rand())),1,5+floor(rand() +100)),case floor(rand()*10)mod 2 when 1 then 'M' else 'F' end ,25-floor(rand()*5) from tmp a,tmp b,tmp c,tmp d; ''' course = '''set @i := 10; insert into course select @i:=@i+1, substr(concat(sha1(rand()), sha1(rand())), 1, 5 + floor(rand() * 40)), 1 + floor(rand() * 100) from tmp a;''' score = '''set @i := 10000; insert into score select @i := @i +1, floor(10001 + rand()*10000), floor(11 + rand()*10), floor(1+rand()*100) from tmp a, tmp b, tmp c, tmp d;''' teacher = '''set @i := 100; insert into teacher select @i:=@i+1, substr(concat(sha1(rand()), sha1(rand())), 1, 5 + floor(rand() * 80)) from tmp a, tmp b;''' if __name__ == "__main__" :cnx = connect_mysql()try :print studentcus_students = cnx.cursor()cus_students.execute(student)cus_students.close()print coursecus_course = cnx.cursor()cus_course.execute(course)cus_course.close()print scorecus_score = cnx.cursor()cus_score.execute(score)cus_score.close()print teachercus_theacher = cnx.cursor()cus_theacher.execute(teacher)cus_theacher.close()print("OK")cnx.commit()except Exception as e :cnx.rollback()print('error')raise efinally:cnx.close()

運行結果：

set @i:= 10000; insert into student select @i:=@i +1,substr(concat(sha1(rand()),sha1(rand())),1,5+floor(rand() +100)),case floor(rand()*10)mod 2 when 1 then 'M' else 'F' end ,25-floor(rand()*5) from tmp a,tmp b,tmp c,tmp d;set @i := 10; insert into course select @i:=@i+1, substr(concat(sha1(rand()), sha1(rand())), 1, 5 + floor(rand() * 40)), 1 + floor(rand() * 100) from tmp a;set @i := 10000; insert into score select @i := @i +1, floor(10001 + rand()*10000), floor(11 + rand()*10), floor(1+rand()*100) from tmp a, tmp b, tmp c, tmp d;set @i := 100; insert into teacher select @i:=@i+1, substr(concat(sha1(rand()), sha1(rand())), 1, 5 + floor(rand() * 80)) from tmp a, tmp b;OK

?驗證：

查詢數據

?

#!/usr/bin/env python #coding:utf8import MySQLdb import codecs def connect_mysql():db_config = {"host":"172.16.61.158","port":3306,"user":"root","passwd":"123456","db":"stu","charset":"utf8",}try:cnx = MySQLdb.connect(**db_config)except Exception as e :raise ereturn cnxif __name__ == "__main__":cnx = connect_mysql()sql = '''select * from student where stdname in (select stdname from student group by stdname having count(1)>1 ) order by stdname;'''print sqltry:cus = cnx.cursor()cus.execute(sql)result = cus.fetchall()for res in result:print rescus.close()cnx.commit()except Exception as e:cnx.rollback()print('error')raise efinally:cnx.close()

運行結果：

select * from student where stdname in (select stdname from student group by stdname having count(1)>1 ) order by stdname; (19001L, u'e03fd17e980627e67c2e1b583f611e4a0855e46e176237ea5e6ba7c2c6a992787447ad57d0a4597d', u'F', 21L) (19021L, u'e03fd17e980627e67c2e1b583f611e4a0855e46e176237ea5e6ba7c2c6a992787447ad57d0a4597d', u'M', 25L) (19028L, u'e03fd17e980627e67c2e1b583f611e4a0855e46e176237ea5e6ba7c2c6a992787447ad57d0a4597d', u'F', 23L)

?

轉載于:https://www.cnblogs.com/pythonlx/p/7881152.html

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