python用PyMySQL操作mysql数据库

1. 安装PyMySQL

使用pip安装PyMySQL

pip install PyMySQL

2. 连接数据库

import pymysql

# 打开数据库连接
db = pymysql.connect(host='localhost', user='root', password='password', database='test', port=3306)

# 创建一个游标对象
cursor = db.cursor()

# 执行SQL语句
cursor.execute('SELECT VERSION()')

# 获取单条数据
data = cursor.fetchone()

print(f'Database version : {data[0]}')

# 关闭游标和数据库连接
cursor.close()
db.close()

3. 插入数据

import pymysql

# 打开数据库连接
db = pymysql.connect(host='localhost', user='root', password='password', database='test', port=3306)

# 创建一个游标对象
cursor = db.cursor()

# SQL 插入语句
sql = "INSERT INTO EMPLOYEE(FIRST_NAME, LAST_NAME, AGE, SEX, INCOME) VALUES ('John', 'Doe', 20, 'M', 2000)"

try:
    # 执行SQL语句
    cursor.execute(sql)
    # 提交到数据库执行
    db.commit()
    print('插入数据成功')
except:
    # 如果发生错误则回滚
    db.rollback()
    print('插入数据失败')

# 关闭游标和数据库连接
cursor.close()
db.close()

4. 查询数据

import pymysql

# 打开数据库连接
db = pymysql.connect(host='localhost', user='root', password='password', database='test', port=3306)

# 创建一个游标对象
cursor = db.cursor()

# SQL 查询语句
sql = "SELECT * FROM EMPLOYEE WHERE INCOME > %s" % (1000)

try:
    # 执行SQL语句
    cursor.execute(sql)
    # 获取所有记录列表
    results = cursor.fetchall()
    for row in results:
        fname = row[0]
        lname = row[1]
        age = row[2]
        sex = row[3]
        income = row[4]
        # 打印结果
        print(f'first_name={fname},last_name={lname},age={age},sex={sex},income={income}')
except:
    print('查询数据失败')

# 关闭游标和数据库连接
cursor.close()
db.close()

5. 更新数据

import pymysql

# 打开数据库连接
db = pymysql.connect(host='localhost', user='root', password='password', database='test', port=3306)

# 创建一个游标对象
cursor = db.cursor()

# SQL 更新语句
sql = "UPDATE EMPLOYEE SET AGE = AGE + 1 WHERE SEX = '%c'" % ('M')

try:
    # 执行SQL语句
    cursor.execute(sql)
    # 提交到数据库执行
    db.commit()
    print('更新数据成功')
except:
    # 发生错误时回滚
    db.rollback()
    print('更新数据失败')

# 关闭游标和数据库连接
cursor.close()
db.close()

6. 删除数据

import pymysql

# 打开数据库连接
db = pymysql.connect(host='localhost', user='root', password='password', database='test', port=3306)

# 创建一个游标对象
cursor = db.cursor()

# SQL 删除语句
sql = "DELETE FROM EMPLOYEE WHERE AGE > %s" % (25)

try:
    # 执行SQL语句
    cursor.execute(sql)
    # 提交到数据库执行
    db.commit()
    print('删除数据成功')
except:
    # 发生错误时回滚
    db.rollback()
    print('删除数据失败')

# 关闭游标和数据库连接
cursor.close()
db.close()