探索异步IO执之前，先说说IO的种类
Python 3.4 开始，标准库里又新增了 asyncio 这个模块。
从原理上来说，它和 Tornado 其实差不多，都是注册 IO 事件，然后在 IO loop 中等待事件发生，然后调用相应的处理函数。
此库提供一个简单的连接对象用法：
import asyncio import aiomysql loop = asyncio.get_event_loop() @asyncio.coroutine def go() pool = yield from aiomysql.create_pool(host=‘127.0.0.1‘, port=3306, user=‘root‘, password=‘‘, db=‘mysql‘, loop=loop) with (yield from pool) as conn: cur = yield from conn.cursor() yield from cur.execute("SELECT 10") # print(cur.description) (r,) = yield from cur.fetchone() assert r == 10 pool.close() yield from pool.wait_closed() loop.run_until_complete(go())
解释：create_pool(minsize=1, maxsize=10, loop=None, **kwargs)
一个协程，创建连接池，连接database
参数：
minsize(int)最小的池子 ， 反之maxsize(int)
loop一个可选的事件循环实例，若未循环，使用 asyncio.get_event_loop()
echo(bool)默认log执行SQL查询
kwargs
Class pool：最重要的是获得连接：
with (yield from pool) as conn: cur = yield from conn.cursor()
connection
该库用来连接MySQL,使用简单的aiomysql.connect(),可以连接一个数据库或者关联池子以连接更多
import asyncio # 举例说明 import aiomysql loop = asyncio.get_event_loop() @asyncio.coroutine def test_example(): conn = yield from aiomysql.connect(host=‘127.0.0.1‘, port=3306, user=‘root‘, password=‘‘, db=‘mysql‘, loop=loop) cur = yield from conn.cursor() yield from cur.execute("SELECT Host,User FROM user") print(cur.description) r = yield from cur.fetchall() print(r) yield from cur.close() conn.close() loop.run_until_complete(test_example())
import asyncio import aiomysql loop = asyncio.get_event_loop() @asyncio.coroutine def test_example(): conn = yield from aiomysql.connect(host=‘127.0.0.1‘, port=3306, user=‘root‘, password=‘‘, db=‘mysql‘, loop=loop) # create default cursor cursor = yield from conn.cursor() # execute sql query # 执行sql查询 yield from cursor.execute("SELECT Host, User FROM user") # fetch all results r = yield from cursor.fetchall() # detach cursor from connection yield from cursor.close() # close connection conn.close() loop.run_until_complete(test_example())
原文：https://www.cnblogs.com/devils19/p/10689025.html