数据连接池之DBUtils

配置文件

import pymysql

Database = {
    'creator':pymysql,
    'maxconnections':20,
    'mincached':2,  # 初始化时，链接池中至少创建的空闲的链接，0表示不创建
    'maxcached':5,  # 链接池中最多闲置的链接，0和None不限制
    'maxshared':3,  # 链接池中最多共享的链接数量，0和None表示全部共享。PS: 无用，因为pymysql和MySQLdb等模块的 threadsafety都为1，所有值无论设置为多少，_maxcached永远为0，所以永远是所有链接都共享。
    'blocking':True,  # 连接池中如果没有可用连接后，是否阻塞等待。True，等待；False，不等待然后报错
    'maxusage':None,  # 一个链接最多被重复使用的次数，None表示无限制
    'setsession':[],  # 开始会话前执行的命令列表。如：["set datestyle to ...", "set time zone ..."]
    'ping':0,

    'default':{
        'host':'127.0.0.1',
        'port':3306,
        'user':'root',
        'pwd':'123456',
        'db':'shop',
        'charset':'utf8'
    }
}

自定义连接池使用类：基于pymysql

from DBUtils.PooledDB import PooledDB
from settings import Database


class SQLHelper:
    def __init__(self):
        self.pool = PooledDB(
            creator=Database['creator'],  # 使用链接数据库的模块
            maxconnections=Database['maxconnections'],  # 连接池允许的最大连接数，0和None表示不限制连接数
            mincached=Database['mincached'],  # 初始化时，链接池中至少创建的空闲的链接，0表示不创建
            maxcached=Database['maxcached'],  # 链接池中最多闲置的链接，0和None不限制
            # 链接池中最多共享的链接数量，0和None表示全部共享。PS: 无用，因为pymysql和MySQLdb等模块的 threadsafety都为1，所有值无论设置为多少，_maxcached永远为0，所以永远是所有链接都共享。
            maxshared=Database['maxshared'],
            blocking=Database['blocking'],  # 连接池中如果没有可用连接后，是否阻塞等待。True，等待；False，不等待然后报错
            maxusage=Database['maxusage'],  # 一个链接最多被重复使用的次数，None表示无限制
            setsession=Database['setsession'],  # 开始会话前执行的命令列表。如：["set datestyle to ...", "set time zone ..."]
            # ping MySQL服务端，检查是否服务可用。
            # 如：0 = None = never,
            # 1 = default = whenever it is requested,
            # 2 = when a cursor is created,
            # 4 = when a query is executed,
            # 7 = always
            ping=Database['ping'],
            # 必要的sql连接信息
            host=Database['default']['host'],
            port=Database['default']['port'],
            user=Database['default']['user'],
            password=Database['default']['pwd'],
            database=Database['default']['db'],
            charset=Database['default']['charset']
        )

    def connectDatabase(self):
        conn = self.pool.connection()
        # cursor = conn.cursor(pymysql.cursors.DictCursor)  # 修改为字典返回类型
        cursor = conn.cursor()  # 默认元组返回类型
        return conn, cursor

    def closeconnect(self, conn, cursor):
        cursor.close()
        conn.close()

    def fetch_all(self, sql, params):
        try:
            conn, cursor = self.connectDatabase()
            cursor.execute(sql, params)
            result = cursor.fetchall()
            self.closeconnect(conn, cursor)
            return result
        except Exception as e:
            return False

    def fetch_one(self, sql, params):
        try:
            conn, cursor = self.connectDatabase()
            cursor.execute(sql, params)
            result = cursor.fetchone()
            self.closeconnect(conn, cursor)
            return result
        except Exception as e:
            return False

    def insert_or_update_or_del(self, sql, params):
        try:
            conn, cursor = self.connectDatabase()
            res = cursor.execute(sql, params)
            conn.commit()
            self.closeconnect(conn, cursor)
            return res
        except Exception as e:
            return False

    def insertmany(self, sql, params):
        """
        批量增加数据
        数据格式：[('0', 'xiaxuan'), ('1', 'xiaxuan'), ('2', 'xiaxuan')]
        执行方式：db.insertmany("INSERT INTO demo (demo.age,demo.`name`) VALUES (%s, %s)",values)
        :return: 执行条数
        """
        try:
            conn, cursor = self.connectDatabase()
            res = cursor.executemany(sql, params)
            conn.commit()
            self.closeconnect(conn, cursor)
            return res
        except Exception as e:
            return False


if __name__ == '__main__':
    pass
    # db = SQLHelper()
    # 查询多条
    # res1 = db.fetch_all("select * from ecm_member where user_id=%s", (299))
    # print(res1)

    # 查询条
    # res2 = db.fetch_one("select * from ecm_member where user_id=%s", (299))
    # 新增或修改单条
    # res3 = db.insert_or_update_or_del("INSERT INTO demo (demo.`name`, demo.age) VALUES (%s, %s)",('alex2',88))
    # print(res3)

    # 模拟批量数据
    # values = []
    # for i in range(10,20):
    #     value = (str(i),'alex')
    #     values.append(value)
    # 批量新增数据
    # res4 = db.insertmany("INSERT INTO demo (demo.age,demo.`name`) VALUES (%s, %s)",values)
    # print(res4)
    # 批量删除数据
    # res5 = db.insert_or_update_or_del('DELETE FROM demo WHERE demo.`name` = %s','alex')
    # print(res5)