PythonMySQL-mysql-connector驱动

Python MySQL - mysql-connector 驱动

MySQL 是最流行的关系型数据库管理系统,如果你不熟悉 MySQL,可以阅读我们的

创新互联建站基于成都重庆香港及美国等地区分布式IDC机房数据中心构建的电信大带宽,联通大带宽,移动大带宽,多线BGP大带宽租用,是为众多客户提供专业服务器托管报价,主机托管价格性价比高,为金融证券行业德阳电信服务器托管,ai人工智能服务器托管提供bgp线路100M独享,G口带宽及机柜租用的专业成都idc公司。

本章节我们为大家介绍使用 mysql-connector 来连接使用 MySQL, mysql-connectorMySQL 官方提供的驱动器。

我们可以使用 pip 命令来安装 mysql-connector

python -m pip install mysql-connector

使用以下代码测试 mysql-connector 是否安装成功:

demo_mysql_test.py:

import

mysql
.
connector

执行以上代码,如果没有产生错误,表明安装成功。

意:如果你的 MySQL 是 8.0 版本,密码插件验证方式发生了变化,早期版本为 mysql_native_password,8.0 版本为 caching_sha2_password,所以需要做些改变:

先修改 my.ini 配置:

[mysqld]
default_authentication_plugin=mysql_native_password

然后在 mysql 下执行以下命令来修改密码:

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '新密码';

更多内容可以参考:。


创建数据库连接

可以使用以下代码来连接数据库:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
# 数据库主机地址

user
=
"
yourusername
"
,
# 数据库用户名

passwd
=
"
yourpassword
"

# 数据库密码

)

print
(
mydb
)

创建数据库

创建数据库使用 "CREATE DATABASE" 语句,以下创建一个名为 runoob_db 的数据库:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
CREATE DATABASE runoob_db
"
)

创建数据库前我们也可以使用 "SHOW DATABASES" 语句来查看数据库是否存在:

demo_mysql_test.py:

输出所有数据库列表:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
SHOW DATABASES
"
)

for

x

in

mycursor
:
print
(
x
)

或者我们可以直接连接数据库,如果数据库不存在,会输出错误信息:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)


创建数据表

创建数据表使用 "CREATE TABLE" 语句,创建数据表前,需要确保数据库已存在,以下创建一个名为 sites 的数据表:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
CREATE TABLE sites (name VARCHAR(255), url VARCHAR(255))
"
) 执行成功后,我们可以看到数据库创建的数据表 sites,字段为 name 和 url。

我们也可以使用 "SHOW TABLES" 语句来查看数据表是否已存在:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
SHOW TABLES
"
)

for

x

in

mycursor
:
print
(
x
)

主键设置

创建表的时候我们一般都会设置一个主键(PRIMARY KEY),我们可以使用 "INT AUTO_INCREMENT PRIMARY KEY" 语句来创建一个主键,主键起始值为 1,逐步递增。

如果我们的表已经创建,我们需要使用 ALTER TABLE 来给表添加主键:

demo_mysql_test.py:

给 sites 表添加主键。

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
ALTER TABLE sites ADD COLUMN id INT AUTO_INCREMENT PRIMARY KEY
"
)

如果你还未创建 sites 表,可以直接使用以下代码创建。

demo_mysql_test.py:

给表创建主键。

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
CREATE TABLE sites (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255), url VARCHAR(255))
"
)


插入数据

插入数据使用 "INSERT INTO" 语句:

demo_mysql_test.py:

向 sites 表插入一条记录。

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
INSERT INTO sites (name, url) VALUES (%s, %s)
"

val
=
(
"
RUNOOB
"
,
"
https://www.runoob.com
"
)

mycursor
.
execute
(
sql
,
val
)

mydb
.
commit
(
)

# 数据表内容有更新,必须使用到该语句

print
(
mycursor
.
rowcount
,
"
记录插入成功。
"
)

执行代码,输出结果为:

1 记录插入成功

批量插入

批量插入使用 executemany() 方法,该方法的第二个参数是一个元组列表,包含了我们要插入的数据:

demo_mysql_test.py:

向 sites 表插入多条记录。

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
INSERT INTO sites (name, url) VALUES (%s, %s)
"

val
=
[

(
'
Google
'
,
'
https://www.google.com
'
)
,
(
'
Github
'
,
'
https://www.github.com
'
)
,
(
'
Taobao
'
,
'
https://www.taobao.com
'
)
,
(
'
stackoverflow
'
,
'
https://www.stackoverflow.com/
'
)

]

mycursor
.
executemany
(
sql
,
val
)

mydb
.
commit
(
)

# 数据表内容有更新,必须使用到该语句

print
(
mycursor
.
rowcount
,
"
记录插入成功。
"
)

执行代码,输出结果为:

4 记录插入成功。

执行以上代码后,我们可以看看数据表的记录:

如果我们想在数据记录插入后,获取该记录的 ID ,可以使用以下代码:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
INSERT INTO sites (name, url) VALUES (%s, %s)
"

val
=
(
"
Zhihu
"
,
"
https://www.zhihu.com
"
)

mycursor
.
execute
(
sql
,
val
)

mydb
.
commit
(
)

print
(
"
1 条记录已插入, ID:
"
,
mycursor
.
lastrowid
)

执行代码,输出结果为:

1 条记录已插入, ID: 6

查询数据

查询数据使用 SELECT 语句:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
SELECT * FROM sites
"
)

myresult
=
mycursor
.
fetchall
(
)

# fetchall() 获取所有记录

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')
(3, 'Github', 'https://www.github.com')
(4, 'Taobao', 'https://www.taobao.com')
(5, 'stackoverflow', 'https://www.stackoverflow.com/')
(6, 'Zhihu', 'https://www.zhihu.com')

也可以读取指定的字段数据:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
SELECT name, url FROM sites
"
)

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

('RUNOOB', 'https://www.runoob.com')
('Google', 'https://www.google.com')
('Github', 'https://www.github.com')
('Taobao', 'https://www.taobao.com')
('stackoverflow', 'https://www.stackoverflow.com/')
('Zhihu', 'https://www.zhihu.com')

如果我们只想读取一条数据,可以使用 fetchone() 方法:

demo_mysql_test.py:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
SELECT * FROM sites
"
)

myresult
=
mycursor
.
fetchone
(
)

print
(
myresult
)

执行代码,输出结果为:

(1, 'RUNOOB', 'https://www.runoob.com')

where 条件语句

如果我们要读取指定条件的数据,可以使用 where 语句:

demo_mysql_test.py

读取 name 字段为 RUNOOB 的记录:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
SELECT * FROM sites WHERE name ='RUNOOB'
"

mycursor
.
execute
(
sql
)

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

(1, 'RUNOOB', 'https://www.runoob.com')

也可以使用通配符 %:

demo_mysql_test.py

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
SELECT * FROM sites WHERE url LIKE '%oo%'
"

mycursor
.
execute
(
sql
)

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')

为了防止数据库查询发生 SQL 注入的攻击,我们可以使用 %s 占位符来转义查询的条件:

demo_mysql_test.py

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
SELECT * FROM sites WHERE name = %s
"

na
=
(
"
RUNOOB
"
,
)

mycursor
.
execute
(
sql
,
na
)

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

排序

查询结果排序可以使用 ORDER BY 语句,默认的排序方式为升序,关键字为 ASC,如果要设置降序排序,可以设置关键字 DESC

demo_mysql_test.py

按 name 字段字母的升序排序:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
SELECT * FROM sites ORDER BY name
"

mycursor
.
execute
(
sql
)

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

(3, 'Github', 'https://www.github.com')
(2, 'Google', 'https://www.google.com')
(1, 'RUNOOB', 'https://www.runoob.com')
(5, 'stackoverflow', 'https://www.stackoverflow.com/')
(4, 'Taobao', 'https://www.taobao.com')
(6, 'Zhihu', 'https://www.zhihu.com')

降序排序实例:

demo_mysql_test.py

按 name 字段字母的降序排序:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
SELECT * FROM sites ORDER BY name DESC
"

mycursor
.
execute
(
sql
)

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

(6, 'Zhihu', 'https://www.zhihu.com')
(4, 'Taobao', 'https://www.taobao.com')
(5, 'stackoverflow', 'https://www.stackoverflow.com/')
(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')
(3, 'Github', 'https://www.github.com')

Limit

如果我们要设置查询的数据量,可以通过 "LIMIT" 语句来指定

demo_mysql_test.py

读取前 3 条记录:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
SELECT * FROM sites LIMIT 3
"
)

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')
(3, 'Github', 'https://www.github.com')

也可以指定起始位置,使用的关键字是 OFFSET

demo_mysql_test.py

从第二条开始读取前 3 条记录:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

mycursor
.
execute
(
"
SELECT * FROM sites LIMIT 3 OFFSET 1
"
)

# 0 为 第一条,1 为第二条,以此类推

myresult
=
mycursor
.
fetchall
(
)

for

x

in

myresult
:
print
(
x
)

执行代码,输出结果为:

(2, 'Google', 'https://www.google.com')
(3, 'Github', 'https://www.github.com')
(4, 'Taobao', 'https://www.taobao.com')

删除记录

删除记录使用 "DELETE FROM" 语句:

demo_mysql_test.py

删除 name 为 stackoverflow 的记录:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
DELETE FROM sites WHERE name = 'stackoverflow'
"

mycursor
.
execute
(
sql
)

mydb
.
commit
(
)

print
(
mycursor
.
rowcount
,
"
条记录删除
"
)

执行代码,输出结果为:

1  条记录删除

注意:要慎重使用删除语句,删除语句要确保指定了 WHERE 条件语句,否则会导致整表数据被删除。

为了防止数据库查询发生 SQL 注入的攻击,我们可以使用 %s 占位符来转义删除语句的条件:

demo_mysql_test.py

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
DELETE FROM sites WHERE name = %s
"

na
=
(
"
stackoverflow
"
,
)

mycursor
.
execute
(
sql
,
na
)

mydb
.
commit
(
)

print
(
mycursor
.
rowcount
,
"
条记录删除
"
)

执行代码,输出结果为:

1  条记录删除

更新表数据

数据表更新使用 "UPDATE" 语句:

demo_mysql_test.py

将 name 为 Zhihu 的字段数据改为 ZH:

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
UPDATE sites SET name = 'ZH' WHERE name = 'Zhihu'
"

mycursor
.
execute
(
sql
)

mydb
.
commit
(
)

print
(
mycursor
.
rowcount
,
"
条记录被修改
"
)

执行代码,输出结果为:

1  条记录被修改

注意:UPDATE 语句要确保指定了 WHERE 条件语句,否则会导致整表数据被更新。

为了防止数据库查询发生 SQL 注入的攻击,我们可以使用 %s 占位符来转义更新语句的条件:

demo_mysql_test.py

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
UPDATE sites SET name = %s WHERE name = %s
"

val
=
(
"
Zhihu
"
,
"
ZH
"
)

mycursor
.
execute
(
sql
,
val
)

mydb
.
commit
(
)

print
(
mycursor
.
rowcount
,
"
条记录被修改
"
)

执行代码,输出结果为:

1  条记录被修改

删除表

删除表使用 "DROP TABLE" 语句, IF EXISTS 关键字是用于判断表是否存在,只有在存在的情况才删除:

demo_mysql_test.py

import

mysql
.
connector

mydb
=
mysql
.
connector
.
connect
(

host
=
"
localhost
"
,
user
=
"
root
"
,
passwd
=
"
123456
"
,
database
=
"
runoob_db
"

)

mycursor
=
mydb
.
cursor
(
)

sql
=
"
DROP TABLE IF EXISTS sites
"

# 删除数据表 sites

mycursor
.
execute
(
sql
)

网页标题:PythonMySQL-mysql-connector驱动
新闻来源:http://www.mswzjz.cn/qtweb/news7/503357.html

攀枝花网站建设、攀枝花网站运维推广公司-贝锐智能,是专注品牌与效果的网络营销公司;服务项目有等

广告

声明:本网站发布的内容(图片、视频和文字)以用户投稿、用户转载内容为主,如果涉及侵权请尽快告知,我们将会在第一时间删除。文章观点不代表本网站立场,如需处理请联系客服。电话:028-86922220;邮箱:631063699@qq.com。内容未经允许不得转载,或转载时需注明来源: 贝锐智能