pymysql 连接池

Posted 2020-11-14 九尘

pymysql连接池

import pymysql
from DBUtils.PooledDB import PooledDB, SharedDBConnection
‘‘‘
连接池
‘‘‘
class MysqlPool(object):

    def __init__(self):
        self.POOL = PooledDB(
            creator=pymysql,  # 使用链接数据库的模块
            maxconnections=6,  # 连接池允许的最大连接数，0和None表示不限制连接数
            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,
            # 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
            host=‘127.0.0.1‘,
            port=3306,
            user=‘root‘,
            password=‘root‘,
            database=‘test‘,
            charset=‘utf8‘
        )
    def __new__(cls, *args, **kw):
        ‘‘‘
        启用单例模式
        :param args:
        :param kw:
        :return:
        ‘‘‘
        if not hasattr(cls, ‘_instance‘):
            cls._instance = object.__new__(cls)
        return cls._instance

    def connect(self):
        ‘‘‘
        启动连接
        :return:
        ‘‘‘
        conn = self.POOL.connection()
        cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
        return conn, cursor

    def connect_close(self,conn, cursor):
        ‘‘‘
        关闭连接
        :param conn:
        :param cursor:
        :return:
        ‘‘‘
        cursor.close()
        conn.close()

    def fetch_all(self,sql, args):
        ‘‘‘
        批量查询
        :param sql:
        :param args:
        :return:
        ‘‘‘
        conn, cursor = self.connect()

        cursor.execute(sql, args)
        record_list = cursor.fetchall()
        self.connect_close(conn, cursor)

        return record_list

    def fetch_one(self,sql, args):
        ‘‘‘
        查询单条数据
        :param sql:
        :param args:
        :return:
        ‘‘‘
        conn, cursor = self.connect()
        cursor.execute(sql, args)
        result = cursor.fetchone()
        self.connect_close(conn, cursor)

        return result

    def insert(self,sql, args):
        ‘‘‘
        插入数据
        :param sql:
        :param args:
        :return:
        ‘‘‘
        conn, cursor = self.connect()
        row = cursor.execute(sql, args)
        conn.commit()
        self.connect_close(conn, cursor)
        return row

 

操作

#实例化
mp=MysqlPool()
‘‘‘
查询单条
‘‘‘
username=‘admin‘
data = mp.fetch_one("select id,nickname from userinfo where user=%s",(username,))
print(data)
‘‘‘
批量读取

‘‘‘
data = mp.fetch_all("select * from record where user_id=%s",(1,))
print(data)
‘‘‘
插入数据
‘‘‘

data = mp.insert("insert into record(line,ctime,user_id)values(%s,%s,%s)",(22,‘2019-11-11‘,1))
print(data)