吴裕雄--天生自然 PYTHON3开发学习：MySQL - mysql-connector 驱动

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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd=""
)

mycursor = mydb.cursor()

mycursor.execute("CREATE DATABASE runoob_db")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd=""
)

mycursor = mydb.cursor()

mycursor.execute("SHOW DATABASES")

for x in mycursor:
  print(x)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

mycursor.execute("CREATE TABLE sites (name VARCHAR(255), url VARCHAR(255))")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

mycursor.execute("SHOW TABLES")

for x in mycursor:
  print(x)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

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

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

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

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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。")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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。")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

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

myresult = mycursor.fetchall()

for x in myresult:
  print(x)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

mycursor.execute("SELECT * FROM sites")

myresult = mycursor.fetchone()

print(myresult)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

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

myresult = mycursor.fetchall()

for x in myresult:
  print(x)

Python 3 教程
Python3 教程
Python3 环境搭建
Python3 基础语法
Python3 基本数据类型
Python3 解释器
Python3 注释
Python3 运算符
Python3 数字(Number)
Python3 字符串
Python3 列表
Python3 元组
Python3 字典
Python3 集合
Python3 编程第一步
Python3 条件控制
Python3 循环语句
Python3 迭代器与生成器
Python3 函数
Python3 数据结构
Python3 模块
Python3 输入和输出
Python3 File
Python3 OS
Python3 错误和异常
Python3 面向对象
Python3 标准库概览
Python3 实例
Python 测验

Python3 高级教程
Python3 正则表达式
Python3 CGI编程
Python3 MySQL(mysql-connector)
Python3 MySQL(PyMySQL)
Python3 网络编程
Python3 SMTP发送邮件
Python3 多线程
Python3 XML 解析
Python3 JSON
Python3 日期和时间
Python3 内置函数
Python MongoDB
Python uWSGI 安装配置
 Python3 CGI编程 Python3 MySQL 数据库连接 – PyMySQL 驱动
Python MySQL - mysql-connector 驱动
MySQL 是最流行的关系型数据库管理系统，如果你不不熟悉 MySQL，可以阅读我们的 MySQL 教程。

本章节我们为大家介绍使用 mysql-connector 来连接使用 MySQL， mysql-connector 是 MySQL 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。

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=""
)

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=""
)

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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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="",
  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)

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  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")

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="",
  database="runoob_db"
)
mycursor = mydb.cursor()

sql = "DROP TABLE IF EXISTS sites"  # 删除数据表 sites

mycursor.execute(sql)