Python 操作 MySQL 之 PyMySQL

1.pymysql 介绍

       Python 中连接 MySQL 服务器有两个库，分别为 PyMySQL 和 MySQLdb，

       PyMySQL 是在 Python 3.x 版本中用于连接 MySQL 服务器的一个库，MySQLdb 只支持到 Python3.4，如果是 Python3.5+ 以上的版本，安装时会报缺少包。

       两者使用方法一样，即使在 Python3.4 以下版本中安装 MySQLdb 也总是报缺少各种包，网上查询的解决方法也不可以，PyMySQL 既支持 Python 2 也支持 Python 3，安装简单方便，所以建议使用 PyMySQL

2.pymysql 安装

安装命令如下

pip install PyMySQL

有些之前的项目中依然使用的是MySQLdb库，可以使用如下命令安装

pip install MySQL-Python --user --global-option=build_ext --global-option="-I/usr/local/opt/openssl/include" --global-option="-L/usr/local/opt/openssl/lib"

3.pymysql 使用

笔者代码中使用了 logging 日志模块，没有安装的使用如下命令安装即可

pip install logging

代码：

#!/usr/bin/python
# -*- coding: UTF-8 -*-

import logging
import pymysql
import pytz
import time
import traceback

"""
    日志配置
        level=日志等级
        datefmt=时间格式
        format=日志格式
"""
logging.basicConfig(
    level=logging.INFO,
    datefmt='%Y-%m-%d %H:%M:%S',
    format='%(asctime)s [%(levelname)s] %(message)s'
)


class Constants(object):
    TIMEZONE = pytz.timezone('Asia/Shanghai')

    MYSQL_KEY_HOST = "host"
    MYSQL_KEY_USER = "user"
    MYSQL_KEY_PASSWORD = "password"
    MYSQL_KEY_PORT = "port"
    MYSQL_KEY_DATABASE = "database"


class MySQLDBHelper(object):
    """
        初始化连接
    """
    def __init__(self, config):
        host = config[Constants.MYSQL_KEY_HOST]
        if host is None:
            raise ValueError("Parameter [host] is None.")

        port = config[Constants.MYSQL_KEY_PORT]
        if port is None:
            raise ValueError("Parameter [port] is None.")

        username = config[Constants.MYSQL_KEY_USER]
        if username is None:
            raise ValueError("Parameter [username] is None.")

        password = config[Constants.MYSQL_KEY_PASSWORD]
        if password is None:
            raise ValueError("Parameter [password] is None.")

        database = config[Constants.MYSQL_KEY_DATABASE]
        if database is None:
            raise ValueError("Parameter [database] is None.")

        logging.debug("[%s] 数据库初始化>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>开始" % database)
        start = time.time()

        self.host = host
        self.username = username
        self.password = password
        self.port = port
        self.database = database

        self.conn = None
        self.cursor = None

        try:
            self.conn = pymysql.connect(**config)
            self.cursor = self.conn.cursor()
            end = time.time()
            logging.debug("[%s] 数据库初始化>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>结束" % database)
            logging.info("[%s] 数据库初始化成功。耗时：%d ms。" % (database, (end - start)))
        except Exception as e:
            logging.error("数据库初始化失败!")
            logging.error(traceback.format_exc())

    """
        释放资源
    """
    def close(self):
        try:
            if not self.conn:
                self.conn.close()
        except Exception as e:
            logging.error("数据库连接释放异常!")
            logging.error(traceback.format_exc())

    """
        创建表
    """
    def create_table(self, sql):
        try:
            logging.info("[%s] SQL >>> [%s]" % (self.database, sql))
            self.cursor.execute(sql)
            self.conn.commit()
        except Exception as e:
            logging.error(traceback.format_exc())

    """
        执行查询 SQL 语句
        :param str sql: 查询sql
        :param bool single: 是否查询单个结果集，默认False
        
        :return: 返回查询数据
        :rtype: list tuple [(e1, e2, ...), (e1, e2, ...), ...]
    """
    def execute_query(self, sql, single=False):
        try:
            logging.info("[%s] SQL >>> [%s]" % (self.database, sql))
            self.cursor.execute(sql)
            if single:
                result_tuple = self.cursor.fetchone()
            else:
                result_tuple = self.cursor.fetchall()
            return result_tuple
        except Exception as e:
            logging.error(traceback.format_exc())

    """
        执行 SQL 语句
        :param str sql: 插入、删除、修改

        :return: 返回受影响行数
        :rtype: int
    """
    def execute_commit(self, sql):
        try:
            logging.info("[%s] SQL >>> [%s]" % (self.database, sql))
            affect_rows = self.cursor.execute(sql)
            self.conn.commit()
            return affect_rows
        except Exception as e:
            self.conn.rollback()
            logging.error(traceback.format_exc())

    """
        批量插入
        :param str sql: 插入

        :return: 返回受影响行数
        :rtype: int
    """
    def insert_many(self, sql, values):
        try:
            affect_rows = self.cursor.executemany(sql, values)
            self.conn.commit()
            return affect_rows
        except Exception as e:
            self.conn.rollback()
            logging.error("[%s] SQL >>> [%s] param >>> %s" % (self.database, sql, values))
            logging.error(traceback.format_exc())


if __name__ == '__main__':
    # 初始化连接
    config = {
        Constants.MYSQL_KEY_HOST: '127.0.0.1',
        Constants.MYSQL_KEY_PORT: 3306,
        Constants.MYSQL_KEY_USER: 'root',
        Constants.MYSQL_KEY_PASSWORD: '123456',
        Constants.MYSQL_KEY_DATABASE: 'test_db'
    }

    db = MySQLDBHelper(config=config)

    # 创建表
    create_table_sql = """
                        CREATE TABLE IF NOT EXISTS `students` (
                          `id` int(11) NOT NULL AUTO_INCREMENT,
                          `name` varchar(50) NOT NULL,
                          `age` int(11) NOT NULL,
                          `gender` int(11) NOT NULL,
                          `address` varchar(100) NOT NULL,
                          `email` varchar(50) NOT NULL,
                          PRIMARY KEY (`id`)
                        ) ENGINE=InnoDB DEFAULT CHARSET=utf8"""
    db.create_table(create_table_sql)

    # 插入数据
    name = "张三"
    age = 18
    gender = 1
    address = "北京朝阳"
    email = "[email protected]"
    insert_sql = """insert into students(`name`, `age`, `gender`, `address`, `email`) values ('%s', %d, %d, '%s', '%s')""" % (name, age, gender, address, email)
    db.execute_commit(insert_sql)

    # 批量插入数据
    insert_many_sql = """insert into students(`name`, `age`, `gender`, `address`, `email`) values (%s, %s, %s, %s, %s)"""
    values = [
        ("李丽", 20, 0, "北京海淀", "[email protected]"),
        ("李四", 21, 1, "天津南开", "[email protected]"),
        ("孙俪", 19, 0, "北京东城", "[email protected]"),
        ("赵钱", 22, 1, "辽宁大连", "[email protected]"),
        ("王五", 20, 1, "河北石家庄", "[email protected]")
    ]
    db.insert_many(insert_many_sql, values)

    # 更新数据
    name = "张三"
    age = 22
    address = "河北保定"
    update_sql = """update students set `age` = %d, `address` = '%s' where `name` = '%s'""" % (age, address, name)
    db.execute_commit(update_sql)

    # 删除数据
    name = "张三"
    delete_sql = """delete from students where `name` = '%s'""" % name
    db.execute_commit(delete_sql)

    # 释放连接
    db.close()

运行结果：

2019-10-31 19:20:39 [INFO] [test_db] 数据库初始化成功。耗时：0 ms。
2019-10-31 19:20:39 [INFO] [test_db] SQL >>> [
                        CREATE TABLE IF NOT EXISTS `students` (
                          `id` int(11) NOT NULL AUTO_INCREMENT,
                          `name` varchar(50) NOT NULL,
                          `age` int(11) NOT NULL,
                          `gender` int(11) NOT NULL,
                          `address` varchar(100) NOT NULL,
                          `email` varchar(50) NOT NULL,
                          PRIMARY KEY (`id`)
                        ) ENGINE=InnoDB DEFAULT CHARSET=utf8]
2019-10-31 19:20:39 [INFO] [test_db] SQL >>> [insert into students(`name`, `age`, `gender`, `address`, `email`) values ('张三', 18, 1, '北京朝阳', '[email protected]')]
2019-10-31 19:20:39 [INFO] [test_db] SQL >>> [update students set `age` = 22, `address` = '河北保定' where `name` = '张三']
2019-10-31 19:20:39 [INFO] [test_db] SQL >>> [delete from students where `name` = '张三']