python-learning-第二季-数据库编程
https://www.bjsxt.com/down/8468.html
代码实现:
#coding:utf-
#导入模块
import sqlite3 #创建connect连接
con = sqlite3.connect('./sqlitedb/demo.db')
print(con) #查看连接是否成功生成,<sqlite3.Connection object at 0x10ae6b3b0> #创建游标对象
cur = con.cursor() #编写创建表的sql语句
sql = '''create table t_person(
pno INTEGER primary key autoincrement,
pname VARCHAR not null,
age INTEGER
)''' try:
#执行说sql语句
cur.execute(sql)
print('创建表成功')
except Exception as e:
print(e)
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x106ded3b0>
创建表成功
操作sqlite3数据库插入数据
#coding:utf-
#导入模块
import sqlite3 #创建connect连接
con = sqlite3.connect('./sqlitedb/demo.db')
print(con) #查看连接是否成功生成,<sqlite3.Connection object at 0x10ae6b3b0> #创建游标对象
cur = con.cursor() #pno是自增长的,可不赋值
#(?,?)表示占位符,在执行时会传入
sql = 'insert into t_person(pname, age) values (?,?)'
try:
#执行说sql语句
cur.execute(sql, ('张三', ))
#提交事务
con.commit()
print('插入成功')
except Exception as e:
print(e)
#回滚
con.rollback()
print('插入数据失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x10c6ac3b0>
插入成功 Process finished with exit code
插入多条数据:
#coding:utf-
#导入模块
import sqlite3 #创建connect连接
con = sqlite3.connect('./sqlitedb/demo.db')
print(con) #查看连接是否成功生成,<sqlite3.Connection object at 0x10ae6b3b0> #创建游标对象
cur = con.cursor() #pno是自增长的,可不赋值
#(?,?)表示占位符,在执行时会传入
sql = 'insert into t_person(pname, age) values (?,?)'
try:
#执行插入多条sql语句
cur.executemany(sql, [('小李', ), ('小明', ), ('小雨', )])
#提交事务
con.commit()
print('插入多条数据成功')
except Exception as e:
print(e)
#回滚
con.rollback()
print('插入多条数据失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x1019fd3b0>
插入多条数据成功 Process finished with exit code
操作sqlite3数据库查询数据
#coding:utf-
#导入模块
import sqlite3 #创建connect连接
con = sqlite3.connect('./sqlitedb/demo.db')
print(con) #查看连接是否成功生成,<sqlite3.Connection object at 0x10ae6b3b0> #创建游标对象
cur = con.cursor() sql = 'select * from t_person'
try:
#执行查询所有sql内容
cur.execute(sql)
#获取所有数据
person_all = cur.fetchall() #返回的是数组
#遍历输出
for p in person_all:
print(p) except Exception as e:
print(e)
print('查询失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x105f903b0>
(, '张三', )
(, '小李', )
(, '小明', )
(, '小雨', ) Process finished with exit code
查询一条:
#coding:utf-
#导入模块
import sqlite3 #创建connect连接
con = sqlite3.connect('./sqlitedb/demo.db')
print(con) #查看连接是否成功生成,<sqlite3.Connection object at 0x10ae6b3b0> #创建游标对象
cur = con.cursor() sql = 'select * from t_person'
try:
#执行查询所有数据sql语句
cur.execute(sql)
#获取一条数据
person = cur.fetchone()
print(person) except Exception as e:
print(e)
print('查询失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x1092793b0>
(, '张三', ) Process finished with exit code
修改数据:
#coding:utf-
#导入模块
import sqlite3 #创建connect连接
con = sqlite3.connect('./sqlitedb/demo.db')
print(con) #查看连接是否成功生成,<sqlite3.Connection object at 0x10ae6b3b0> #创建游标对象
cur = con.cursor() sql = 'update t_person set pname=? where pno=?'
try:
#执行修改sql语句
cur.execute(sql,('张四',))
#提交事务
con.commit()
print('修改成功') except Exception as e:
print(e)
#回滚
con.rollback()
print('修改失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x10d4bb3b0>
修改成功 Process finished with exit code
查询可见修改成功:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x10ab113b0>
(, '张四', ) Process finished with exit code
删除数据:
#coding:utf-
#导入模块
import sqlite3 #创建connect连接
con = sqlite3.connect('./sqlitedb/demo.db')
print(con) #查看连接是否成功生成,<sqlite3.Connection object at 0x10ae6b3b0> #创建游标对象
cur = con.cursor() sql = 'delete from t_person where pno=?'
try:
#执行删除sql语句
cur.execute(sql,(,)) #元组仅有一个参数,必需有面加逗号,保证参数类型为元组
#提交事务
con.commit()
print('删除成功') except Exception as e:
print(e)
#回滚
con.rollback()
print('删除失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x101ebb3b0>
删除成功 Process finished with exit code
此时查看第一条数据为:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<sqlite3.Connection object at 0x101e623b0>
(, '小李', ) Process finished with exit code
MySQL数据库的下载
我已经安装好了,这里省略,去官网下载即可,端口默认3306
安装对应的模块PyMySQL
以为之前的deeplearning中的可用在这,发现不行,所以就重新下载了:
(venv) (base) userdeMBP:python3 user$ pip install PyMySQL
Collecting PyMySQL
Using cached https://files.pythonhosted.org/packages/ed/39/15045ae46f2a123019aa968dfcba0396c161c20f855f11dea6796bcaae95/PyMySQL-0.9.3-py2.py3-none-any.whl
Installing collected packages: PyMySQL
Successfully installed PyMySQL-0.9.
我已经下载好了
操作MySQL数据库创建表
先是创建了数据库python_db:
首先先连接:
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=)
print(con)
成功连接:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
<pymysql.connections.Connection object at 0x103d3f6a0> Process finished with exit code
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=) #创建游标对象
cur = con.cursor() #编写创建表的sql,score总共三位,小数点占一位
sql = '''
create table t_student(
sno int primary key auto_increment,
sname varchar() not null,
age int(),
score float(,)
)
''' try:
#执行创建表的sql
cur.execute(sql)
print('创建成功')
except Exception as e:
print(e)
print('创建失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
创建成功 Process finished with exit code
查看成功创建:
插入数据:
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=) #创建游标对象
cur = con.cursor() #插入数据
sql = 'insert into t_student(sname, age, score) values(%s, %s, %s)' try:
#执行创建表的sql
cur.execute(sql, ('王一', , ))
#提交事务
con.commit()
print('插入成功')
except Exception as e:
print(e)
con.rollback()
print('插入失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
插入成功 Process finished with exit code
查看:
插入多条数据:
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=) #创建游标对象
cur = con.cursor() #插入数据
sql = 'insert into t_student(sname, age, score) values(%s, %s, %s)'
temp = [('王二', , ), ('王三', , )]
try:
#执行创建表的sql
cur.executemany(sql, temp)
#提交事务
con.commit()
print('插入成功')
except Exception as e:
print(e)
con.rollback()
print('插入失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
插入成功 Process finished with exit code
查看:
查询数据
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=) #创建游标对象
cur = con.cursor() #查询多个数据
sql = 'select * from t_student where age >= 19' try:
#执行创建表的sql
cur.execute(sql)
students = cur.fetchall()
print(students)
print('查询成功')
except Exception as e:
print(e)
print('查询失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
((, '王二', , 70.0), (, '王三', , 80.0))
查询成功 Process finished with exit code
查询:
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=) #创建游标对象
cur = con.cursor() #查询多个数据
sql = 'select * from t_student where age >= 19' try:
#执行创建表的sql
cur.execute(sql)
students = cur.fetchall()
for student in students:
print(student[], end = ' ,')
print(student[], end=' ,')
print(student[], end=' ,')
print(student[]) except Exception as e:
print(e)
print('查询失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
,王二 , ,70.0
,王三 , ,80.0 Process finished with exit code
查询一个数据:
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=) #创建游标对象
cur = con.cursor() #查询一个数据
sql = 'select * from t_student where age >= 19' try:
#执行创建表的sql
cur.execute(sql)
student = cur.fetchone()
print(student) except Exception as e:
print(e)
print('查询失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
(, '王二', , 70.0) Process finished with exit code
更新数据:
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=3306) #创建游标对象
cur = con.cursor() #查询一个数据
sql = 'update t_student set sname=%s where sno =%s' try:
#执行创建表的sql
cur.execute(sql, ('王五', 1))
#提交事务
con.commit() print('更新成功') except Exception as e:
print(e)
con.rollback()
print('更新失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
更新成功 Process finished with exit code 0
查看:
删除数据:
#导入pymysql
import pymysql #创建连接
con = pymysql.connect(host='localhost', user='root', password='user78', database='python_db', port=3306) #创建游标对象
cur = con.cursor() #查询一个数据
sql = 'delete from t_student where sname =%s' try:
#执行创建表的sql
cur.execute(sql, ('王五',))
#提交事务
con.commit() print('删除成功') except Exception as e:
print(e)
con.rollback()
print('删除失败')
finally:
#关闭游标
cur.close()
#关闭连接
con.close()
返回:
/Users/user/PycharmProjects/python3/venv/bin/python /Users/user/PycharmProjects/python3/test.py
更新成功 Process finished with exit code 0
查看:
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