为什么要使用pymysql

        在使用Python工作与学习中难免会使用到mysql数据库，使用pymysql三方库可以让我们轻松的对数据库的记录进行操作，如创建、修改，删除表，如增加、删除、修改、查询数据表中的记录，下边记录一下pymysql的使用方法：

---

连接方法 Connect = connect = Connection

# 创建mysql数据库连接
conn = Connection(
    user='root',
    host='192.168.109.135',
    password='test_12345',
    port=3306,
    database='test_db',
    charset='utf8',
    cursorclass=cursors.DictCursor
)

CURSOR种类

        cursor 的种类有四种，默认使用的是Cursor,还有DictCursor，SSCursor，SSDictCursor，Cursor 返回的结果是以元组的形式返回的，DictCursor，是以字典的形式返回的。DictCursor是继承了Cursor与DictCursorMixin，DictCursorMixin里面只有函数两个方法。（可以选择自己需要的返回形式）

INSERT INTO语句（增）

1. 单条数据插入

 data = (1, 'group1', 'group1/M00/00/00/wKhthmT1PGuAXV09AAABFcYZOGg5350.py', 'Upload successed.', 'fdfs.py', '277B', '192.168.109.134', 'fdfs.py')
 with conn.cursor() as cursor:
        # Create a new record
        sql = "INSERT INTO `upload_file` (`Group name`, `Remote file_id`, `Status`, `Local file name`, `Uploaded size`, `Storage IP`, `Filename`)" \
              " VALUES (%s, %s, %s, %s, %s, %s, %s)"
        cursor.execute(sql, data)
        conn.commit()

1. 多条数据插入

 data = ((1, 'group1', 'group1/M00/00/00/wKhthmT1PGuAXV09AAABFcYZOGg5350.py', 'Upload successed.', 'fdfs.py', '277B', '192.168.109.134', 'fdfs.py'), (2, 'group1', 'group1/M00/00/00/wKhthmT1TMKAH20TAAAD-MJMli03267.py', 'Upload successed.', 'fdfs.py', '1016B', '192.168.109.134', 'fdfs.py'), (3, 'group1', 'group1/M00/00/00/wKhthmT1TSqAFhCyAAxZcPR00vw.tar.gz', 'Upload successed.', 'fastdfs-6.06.tar.gz', '790.36KB', '192.168.109.134', 'fastdfs-6.06.tar.gz'), (4, 'group1', 'group1/M00/00/00/wKhthmT1TTCABEUgAABN8HAGbcY.tar.gz', 'Upload successed.', 'fastdfs-nginx-module-1.22.tar.gz', '19.48KB', '192.168.109.134', 'fastdfs-nginx-module-1.22.tar.gz'), (5, 'group1', 'group1/M00/00/00/wKhthmT1TTWAU-W3ABBjHPqFuIs.tar.gz', 'Upload successed.', 'nginx-1.22.1.tar.gz', '1.02MB', '192.168.109.134', 'nginx-1.22.1.tar.gz'), (6, 'group1', 'group1/M00/00/00/wKhthmT1TUCAaierAAKKfr3HBzE.tar.gz', 'Upload successed.', 'libfastcommon-1.0.43.tar.gz', '162.62KB', '192.168.109.134', 'libfastcommon-1.0.43.tar.gz'), (7, 'group1', 'group1/M00/00/00/wKhthmT1TVeANtONAAKKfr3HBzE.tar.gz', 'Upload successed.', '/tmp/libfastcommon-1.0.43.tar.gz', '162.62KB', '192.168.109.134', 'libfastcommon-1.0.43.tar.gz'))
 with conn.cursor() as cursor:
        # Create a new record
        sql = "INSERT INTO `upload_file` (`Group name`, `Remote file_id`, `Status`, `Local file name`, `Uploaded size`, `Storage IP`, `Filename`)" \
              " VALUES (%s, %s, %s, %s, %s, %s, %s)"
        cursor.executemany(sql, data)
        conn.commit()

DELETE  语句（删）

def delete(pk: int):
    """
    delete from table where filed1='';
    :param pk:
    :return:
    """
    with conn.cursor() as cursor:
        # delete a record
        SQL = "delete from `upload_file` where id=%d" % pk
        cursor.execute(SQL)
        conn.commit()

UPDATE SET 语句（改）

def update(pk):
    """update table set column1=value1, column2=value2"""
    with conn.cursor() as cursor:
        # delete a record
        SQL = "update upload_file set Filename='test.txt' where id=%d" % pk
        cursor.execute(SQL)
        conn.commit()

SELECT 语句（查）

1. 多记录查询

    def select(self, pk=None):
        with conn.cursor() as cursor:
            sql = """ SELECT * from `upload_file`"""
            cursor.execute(sql)
            rows = cursor.fetchall()
            print(rows)

1. 单记录查询

    def select(self, pk):
        with conn.cursor() as cursor:
            sql = """ SELECT * from `upload_file` where id=%d""" % pk
            cursor.execute(sql)
            rows = cursor.fetchone()
            print(rows)