回收原因：sqlalchemy对sqlite3和pymysql进行了良好的封装，因此在操作sql时，无需再过多关注底层的sqlite3和pymysql了
pymysql是用Python调用MySQL的包
另一篇文章中讲了pysqlite的操作，pymysql的用法也类似。
连接数据库
import pymysql.cursors
config = {
'host':'127.0.0.1',
'port':3306,
'user':'root',
'password':'zhyea.com',
'db':'employees',
'charset':'utf8mb4',
'cursorclass':pymysql.cursors.DictCursor,
}
# Connect to the database
connection = pymysql.connect(**config)
插入数据
from datetime import date, datetime, timedelta
# 获取明天的时间
tomorrow = datetime.now().date() + timedelta(days=1)
# 执行sql语句
try:
with connection.cursor() as cursor:
# 执行sql语句，插入记录
sql = 'INSERT INTO employees (first_name, last_name, hire_date, gender, birth_date) VALUES (%s, %s, %s, %s, %s)'
cursor.execute(sql, ('Robin', 'Zhyea', tomorrow, 'M', date(1989, 6, 14)));
# 没有设置默认自动提交，需要主动提交，以保存所执行的语句
connection.commit()
finally:
connection.close();
查询
# 获取雇佣日期
hire_start = datetime.date(1999, 1, 1)
hire_end = datetime.date(2016, 12, 31)
# 执行sql语句
try:
with connection.cursor() as cursor:
# 执行sql语句，进行查询
sql = 'SELECT first_name, last_name, hire_date FROM employees WHERE hire_date BETWEEN %s AND %s'
cursor.execute(sql, (hire_start, hire_end))
# 获取查询结果
result = cursor.fetchone()#dict
#result = cursor.fetchmany(2)
#result = cursor.fetchall()#list
print(result)
# 没有设置默认自动提交，需要主动提交，以保存所执行的语句
connection.commit()
finally:
connection.close();
其它
pymysql有个小问题，字段顺序是乱的。
还有mysql官方的Python包：mysql-connector-python，用处差不多，
