小编alf*_*g67的帖子

以下作品:

class DB():
    def __init__(self, host, user, password, db):
        self.conn =  pymysql.connect(
            host = host,
            user = user,
            passwd = password,
            charset = 'utf8',
            cursorclass = pymysql.cursors.DictCursor,
            db = db
        )

        self.cur = self.conn.cursor()

    def execute(self, sql):
        self.cur.execute(sql)

    def fetchone(self):
        return self.cur.fetchone()

cf = DB("localhost", "user", "pass", "db")
cf.execute("SELECT Count(*) FROM Table")
aryRes = cf.fetchone()

但是当我用SSCursor替换DictCursor时,aryRes包含None,我得到:

warnings.warn("Previous unbuffered result was left incomplete")

我尝试了以下所有组合:

import pymysql
import pymysql.cursors
from pymysql import cursors

我还确认以下内容正确返回(未封装):

con = pymysql.connect(
    host = "localhost", 
    user = …

我有一个PHP脚本,用于检查从安全摄像头拍摄的2张静态照片之间的汉明距离.

该表是具有2.4M行的mySQL,由一个Key和4个INT(10)组成.INT(10)已被单独索引,并与Key一起索引,但我没有重要证据表明任何组合比其他组合更快.如果你建议,我可以再试一次.

通过将图像转换为8×16像素来计算汉明权重,并且每四分之一的比特存储在列,pHash0,pHash1 ......等中.

我写了两种方法.第一种方法是使用嵌套的派生表.从理论上讲,每个派生应该检查的数据比它的前身要少.查询是一个准备好的语句,而？字段是我正在检查的文件的pHash [0-3].

Select
    `Key`,
    Bit_Count(T3.pHash3 ^ ?) + T3.BC2 As BC3
  From
    (Select
      *,
      Bit_Count(T2.pHash2 ^ ?) + T2.BC1 As BC2
    From
      (Select
        *,
        Bit_Count(T1.pHash1 ^ ?) + T1.BC0 As BC1
      From
        (Select
          `Key`,
          pHash0,
          pHash1,
          pHash2,
          pHash3,
          Bit_Count(pHash0 ^ ?) As BC0
        From
          files
        Where
          Not pHash0 Is Null And
          Bit_Count(pHash0 ^ ?) < 4) As T1
      Where
        Bit_Count(T1.pHash1 ^ ?) + T1.BC0 < 4) As T2
    Where
      Bit_Count(T2.pHash2 ^ ?) + T2.BC1 < 4) …