{'SID':1,'Date':2018/11/18,'Time':12:17:36}
{'SID':2,'Date':2018/11/18,'Time':12:28:02}
...
...

import pyodbc
import serial
import time
import datetime
import ast
cnxn = pyodbc.connect("Driver={SQL Server Native Client 11.0};"
                      "Server=DESKTOP-H7KQUT1;"
                      "Database=SAOS1;"
                      "Trusted_Connection=yes;")
cursor = cnxn.cursor()
arduino = serial.Serial('COM4', 9600, timeout=.1)


while True:

    data = arduino.readline()[:-2].decode("utf-8")

    if data!="":

        Atd_Date = ast.literal_eval(data)['Date']
        Atd_InTime = ast.literal_eval(data)['Time']
        SID = ast.literal_eval(data)['SID']
        tsql = "INSERT INTO attendance (Atd_Date, Atd_InTime, SID) VALUES (?,?,?);"
        with cursor.execute(tsql,Atd_Date,Atd_InTime,SID):
            print ('Successfuly Inserted!')