MySQLデータベース～～～pymysql MySQLのクライアントに接続

import pymysql
conn = pymysql.connect(
        host = '127.0.0.1', #   
        port = 3306, #    
        user = 'root', #    
        password = '123', #   
        database = 'db1', #       
        charset = 'utf8')
cursor = conn.cursor(pymysql.cursors.DictCursor)
#             ((),(),)
# DictCursor         [{},{},],     fetchone,     {}.
sql = 'select * from t1;'
ret = cursor.execute(sql) # ret       
print(ret)
print(cursor.fetchall())  #       
print(cursor.fetchone())  #       
print(cursor.fetchmany(2)) #       ,        
cursor.scroll(2,'absolute') #       ,                  
cursor.scroll(2,'relative') #       ,                

sql = 'insert into t1 values(1,"liky");'
conn.commit() #             commit

import pymysql
conn = pymysql.connct(
        host = '127.0.0.1', #   
        port = 3306, #    
        user = 'root', #    
        password = '123', #   
        database = 'db1', #       
        charset = 'utf8')
while 1:
    username = input('      :')
    password = input('     :')
    cursor = conn.cursor(pymysql.cursors.DictCursor)
    sql = "select * from userinfo where username = '%s' and password = '%s';"%(username,password)
    #                   ,     'liky--  ,      ;                ,     'liky--      ,sql    --         .
    #  sql    :
    sql = "select * from userinfo where username = %s and password = %s;"
    ret = cursor.execute(sql,[username,password])
    if ret:
        print('    !')
        break
    else:
        print('       ,     !')