基于python的学生管理系统(含数据库版本)

Posted 2020-10-24 jeavenwong

这次支持连接到后台的数据库，直接和数据库进行交互，实现基本的增删查改

  1 #!/usr/bin/python3
  2 # coding=utf-8
  3 """
  4 ***********************help document****************************************
  5 Usage:
  6     this is a simple student grades system,now is simple
  7     when start the programming,you can do following operations
  8     enter \'a\' is to insert data into database
  9     enter \'b\' is to display all data in database
 10     enter \'c\' is to query the specify info in database
 11     enter \'h\' is to see this help dacument
 12     enter \'d\' is to delete someone student\'s info
 13     enter nothing is to do nothing,you can enter again
 14     simple help document is: "a--insert/b--display/c--query/h--help/d--delete/\'\'--default"
 15 Example:
 16     please enter the OPcode: a  then [enter]
 17 *****************************************************************************
 18 
 19 """
 20 
 21 #引入pymysql这个库用来连接数据据
 22 import pymysql
 23 
 24 #打印帮助文档
 25 def help_document():
 26     print(__doc__)
 27 
 28 #在已有的数据库上创建数据库的表
 29 def create_database():
 30     #在mysql中创建数据库student_db
 31     db = pymysql.connect(\'localhost\', \'root\', \'root\')
 32     name = \'student_db\'
 33     cursor = db.cursor()
 34     cursor.execute(\'drop database if exists \' + name)
 35     cursor.execute(\'create database if not exists \' + name)
 36     db.close()
 37     #在数据库student_db中创建数据表student_table
 38     db = pymysql.connect(\'localhost\', \'root\', \'root\', \'student_db\')
 39     cursor = db.cursor()
 40     name = \'student_table\'
 41     cursor.execute(\'drop table if exists \' + name)
 42     sql = """create table student_table(
 43     name varchar(30) primary key not null,
 44     age  varchar(10),
 45     id   varchar(20),
 46     grade  varchar(10))"""
 47     cursor.execute(sql)
 48     db.commit()
 49     db.close()
 50 
 51 #数据库的插入
 52 def insert_db(name,age,id,grade):
 53     db = pymysql.connect(\'localhost\', \'root\', \'root\',\'student_db\')
 54     cursor = db.cursor()
 55     sql = "insert into student_table (name,age,id,grade) values (\'%s\',\'%s\',\'%s\',\'%s\')" % \\
 56           (name,age,id,grade)
 57     cursor.execute(sql)
 58     db.commit()
 59     db.close()
 60 
 61 #打印数据库中所有数据
 62 def display_db():
 63     db = pymysql.connect(\'localhost\', \'root\', \'root\', \'student_db\')
 64     cursor = db.cursor()
 65     sql = "select * from student_table"
 66     try:
 67         cursor.execute(sql)
 68         result = cursor.fetchall()
 69         for row in result:
 70             name = row[0]
 71             age = row[1]
 72             id = row[2]
 73             grade = row[3]
 74             print("name: \'%s\',age: \'%s\',id: \'%s\',grade: \'%s\'" % (name,age,id,grade))
 75         print("that\'s all diaplayed!")
 76     except:
 77         print(\'nothing has been displayed...\')
 78     db.close()
 79 
 80 #数据库的查找
 81 def query_db(name):
 82     db = pymysql.connect(\'localhost\', \'root\', \'root\', \'student_db\')
 83     cursor = db.cursor()
 84     sql = "select * from student_table where name = \'%s\' " % name
 85     try:
 86         cursor.execute(sql)
 87         result = cursor.fetchall()
 88         for row in result:
 89             name1 = row[0]
 90             age1 = row[1]
 91             id1 = row[2]
 92             grade1 = row[3]
 93         print("name: \'%s\',age: \'%s\',id: \'%s\',grade: \'%s\'" % \\
 94               (name1,age1,id1,grade1))
 95         print(\'the query is over!\')
 96     except:
 97         print(\'can not query data!\')
 98     db.close()
 99 
100 #更新数据库
101 def update_db(name,age,id,grade):
102     db = pymysql.connect(\'localhost\', \'root\', \'root\', \'student_db\')
103     cursor = db.cursor()
104     sql = "update student_table set age = \'%s\',id = \'%s\',grade = \'%s\' where name = \'%s\'" % \\
105           (age,id,grade,name)
106     try:
107         cursor.execute(sql)
108         db.commit()
109         print(\'updated successfully!\')
110     except:
111         print(\'can not update data!\')
112     db.close()
113 
114 
115 #数据库的删除
116 def delete_db(name):
117     db = pymysql.connect(\'localhost\', \'root\', \'root\', \'student_db\')
118     cursor = db.cursor()
119     sql = "delete from student_table where name = \'%s\'" % name
120     try:
121         cursor.execute(sql)
122         db.commit()
123         print(\'delete the student info successfully!\')
124     except:
125         print(\'delete failed...\')
126     db.close()
127 
128 # 实现switch-case语句
129 class switch(object):
130     def __init__(self, value):
131         self.value = value
132         self.fall = False
133 
134     def __iter__(self):
135         """Return the match method once, then stop"""
136         yield self.match
137         raise StopIteration
138 
139     def match(self, *args):
140         """Indicate whether or not to enter a case suite"""
141         if self.fall or not args:
142             return True
143         elif self.value in args:  # changed for v1.5, see below
144             self.fall = True
145             return True
146         else:
147             return False
148 
149 #建立一个学生类
150 class student:
151     #构造函数
152     def __init__(self, name, age, id, grade):
153         self.next = None
154         self.name = name
155         self.age = age
156         self.id = id
157         self.grade = grade
158     #每个学生可以输出自己的信息
159     def show(self):
160         print(\'name:\', self.name, \' \', \'age:\', self.age, \' \', \'id:\', self.id, \' \', \'grade:\', self.grade)
161 
162 #建立一个学生列表类
163 class stulist:
164     #构造函数
165     def __init__(self):
166         self.head = student(\'\', 0, 0, 0)
167     #输出数据库中所有的数据
168     def display(self):
169         display_db()
170     #新增学生数据
171     def insert(self):
172         print(\'please enter:\')
173         name = input(\'name:\')
174         age = input(\'age:\')
175         id = input(\'id:\')
176         grade = input(\'grade:\')
177         insert_db(name, age, id, grade)
178 
179     #查询学生数据
180     def query(self):
181         name = input(\'please enter the name you want to query:\')
182         query_db(name)
183 
184     #删除学生数据
185     def delete(self):
186         name = input("please enter the student\'name you want to delete:")
187         delete_db(name)
188 
189 #主函数，程序的入口
190 def main():
191     stulist1 = stulist()
192     user_input = input(\'please enter the OPcode:\')
193     while user_input:
194         print("a--insert/b--display/c--query/h--help/d--delete/\'\'--default")
195         for case in switch(user_input):
196             if case(\'a\'): #按下\'a\'键
197                 stulist1.insert()
198                 user_input = input(\'please enter the OPcode:\')
199                 break
200             if case(\'b\'):  #按下\'b\'键
201                 stulist1.display()
202                 user_input = input(\'please enter the OPcode:\')
203                 break
204             if case(\'c\'):  #按下\'c\'键
205                 stulist1.query()
206                 user_input = input(\'please enter the OPcode:\')
207                 break
208             if case(\'d\'):  #按下\'d\'键
209                 stulist1.delete()
210                 user_input = input(\'please enter your OPcode:\')
211                 break
212             if case(\'h\'):  #按下\'h\'键
213                 help_document()
214                 user_input = input(\'please enter your OPcode:\')
215                 break
216             if case():  # default
217                 print(\'please enter the OPcode...\')
218                 user_input = input(\'please enter the OPcode:\')
219                 break
220 
221 
222 if __name__ == "__main__":
223     #第一次运行程序需要建立新的数据库,需要运行下面注释的一行代码，下次运行得将其注释掉
224     #create_database()
225     main()

结果效果图：

输入\'h\'查看帮助文档

输入\'b\'来查询数据库数据:

 

这个版本还是很粗糙，访问速度也很慢，如果以后还有时间的话，我会做一个界面出来，改进下和数据库的交互方式。