python通过数据库连接池实现mysql数据库增删改查

import pymysql
from DBUtils.PooledDB import PooledDB


class SQLHandler(object):
    def __init__(self, host, port, db_username, db_password, db_name):
        # pip install --default-timeout=100 dbutils
        self.pool = PooledDB(
            # 使用链接数据库的模块import pymysql
            creator=pymysql,
            # 连接池允许的最大连接数，0和None表示不限制连接数
            maxconnections=6,
            # 初始化时，链接池中至少创建的空闲的链接，0表示不创建
            mincached=2,
            # 链接池中最多闲置的链接，0和None不限制
            maxcached=5,
            # 链接池中最多共享的链接数量，0和None表示全部共享。
            # 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=3,
            # 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
            blocking=True,
            # 一个链接最多被重复使用的次数，None表示无限制
            maxusage=None,
            # 开始会话前执行的命令列表。如：["set datestyle to ...", "set time zone ..."]
            setsession=[],
            # 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=0,

            # 数据库信息
            host=host,
            port=int(port),
            user=db_username,
            password=db_password,
            database=db_name,
            charset='utf8'
        )

    def create_conn_cursor(self):
        # 创建连接
        conn = self.pool.connection()
        # 创建游标
        cursor = conn.cursor(pymysql.cursors.DictCursor)
        # 返回conn, cursor
        return conn, cursor

    def fetch_one(self, sql, args):
        conn, cursor = self.create_conn_cursor()
        cursor.execute(sql, args)
        result = cursor.fetchone()
        cursor.close()
        conn.close()
        return result

    def fetch_many(self, sql, args):
        conn, cursor = self.create_conn_cursor()
        cursor.execute(sql)
        result = cursor.fetchmany(args)
        cursor.close()
        conn.close()
        return result

    def fetch_all(self, sql, args):
        conn, cursor = self.create_conn_cursor()
        cursor.execute(sql, args)
        result = cursor.fetchall()
        cursor.close()
        conn.close()
        return result

    def insert_one(self, sql, args):
        conn, cursor = self.create_conn_cursor()
        res = cursor.execute(sql, args)
        conn.commit()
        print(res)
        conn.close()
        return res

    def insert_many(self, sql, args):
        conn, cursor = self.create_conn_cursor()
        res = cursor.executemany(sql, args)
        conn.commit()
        print(res)
        conn.close()
        return res

    def update(self, sql, args):
        conn, cursor = self.create_conn_cursor()
        res = cursor.execute(sql, args)
        conn.commit()
        print(res)
        conn.close()
        return res

    def delete(self, sql, args):
        conn, cursor = self.create_conn_cursor()
        res = cursor.execute(sql, args)
        conn.commit()
        print(res)
        conn.close()
        return res

sqlhelper = SQLHandler("127.0.0.1", 3306, "root", "root", "py")

## 查询
# 指定列名查询
# ret = sqlhelper.fetch_all("select * from user333 where id=%s",(2))
# ret = sqlhelper.fetch_all("select * from user333 where name=%s",('apollo'))
# 显示查询结果第一条
# ret = sqlhelper.fetch_one("select * from user333",None)
# 显示查询结果前两条
# ret = sqlhelper.fetch_many("select * from user333",(2))
# 显示查询结果全部
# ret = sqlhelper.fetch_all("select * from user333", None)
# for (index, item) in enumerate(ret, 1):
#     print(index, item)


## 插入
# 插入一条数据
# 方式1：
# ret = sqlhelper.insert_one("insert into user333 VALUES (%s,%s,%s)",(10,"litch",56))
# 方式2：
#  ret = sqlhelper.insert_one("insert into user333 (name,age)VALUES (%s,%s)",("banana",12))
# 插入多条数据
data = [
    ('apollo88', '288'),
    ('jack88', '218'),
    ('merry88', '298')
]
sql = 'insert into user444(name,age) values(%s,%s);'
ret = sqlhelper.insert_many("insert into user333(name,age) values(%s,%s);",data)


## 更新
# ret = sqlhelper.update("update user333 SET name=%s WHERE id=%s",("Smith",1))


## 删除
# ret = sqlhelper.delete("delete from user333 where name=%s;",[("jack88")])
# print(ret)

 ```

# 插入多条数据补充：表名也可以作为变量传入

data = [(3, 'apollo3', '232'), (24, 'jack4', '264')]
table_name = "test"
sql = "insert into {0} values(%s,%s,%s);".format(table_name)
db3.insert_many(sql , data)

```