Question

我正在努力弄清楚如何在从数据库中读取后清除元组'数据'。

流程：

每隔X分钟，我调用batchUpdate

batchUpdate拉入符合特定条件的记录

我们遍历那些执行更新的记录

流程结束并等待下一个电话

问题：

对函数batchUpdate的每次后续调用都不会产生新数据。元组'data'包含与之前相同的值。

简化示例（仅拉1条记录，每1秒计划一次）：

Update has started
((10938L, u"@anonymized @anonymized House of Cards will be nothing compared  to the Drumpf's!And worst of all is that Americans chose him as president?", u'New York, USA'),)
Update has started
((10938L, u"@anonymized @anonymized House of Cards will be nothing compared to the Drumpf's!And worst of all is that Americans chose him as president?", u'New York, USA'),)
Update has started
((10938L, u"@anonymized @anonymized House of Cards will be nothing compared to the Drumpf's!And worst of all is that Americans chose him as president?", u'New York, USA'),)
Update has started
((10938L, u"@anonymized @anonymized House of Cards will be nothing compared to the Drumpf's!And worst of all is that Americans chose him as president?", u'New York, USA'),)

代码：

class analyzeRecords():
    def batchUpdate(self):

     global data

     #Select up to 1 record

     b.execute(""" SELECT id, tweet,tweet_location_guess FROM rawTweets where compoundScore IS NULL LIMIT 0,1 """)

     #Put that data into a tuple

     data = b.fetchall()

     print(data)

     #print that update has started

     print("Update has started")

     for row in data:
          idMatch = row[0]
          cleanTweet = reduce(lambda x, y: x.replace(y, d[y]), sorted(d, key=lambda i: len(i), reverse=True), row[1].lower())
          sentimentScores = analyzer.polarity_scores(cleanTweet)
          overallScore = sentimentScores["compound"]

          u.execute("""UPDATE rawTweets SET tweet=%s, compoundScore=%s where id=%s""",
                    (cleanTweet, overallScore, idMatch))
          update.commit()

l = task.LoopingCall(analyzeRecords().batchUpdate)
l.start(timeout) # call every sixty seconds

reactor.run()

Answer 1

在您的代码中，您正在执行以下两行：

client.EnableSsl = false;
client.UseDefaultCredentials = false;

总之，这两个语句应该覆盖之前global data data = b.fetchall()变量中的任何内容。

我会指出这个函数似乎不是需要一个全局变量 - 你可以而且可能应该只使用一个局部变量。

无论如何，我认为问题不在于存在一些神秘的剩余数据，除非data对象被定义为这样做。（例如，如果查询中存在错误，或者查询没有返回匹配项，那么它是如何进行通信的？如果它引发或返回您忽略的值，则b.fetchall()可能会返回过时的数据因为你应该检查值而不是调用fetchall ...）

我建议您查看fetchall和execute如何协同工作，并查看您的for循环。我看到fetchall和b.execute以及u.execute。这似乎有许多不同的数据库连接。也许你这样做。或许你复制/粘贴代码，你真的应该做的事情如下：

update.commit

在For循环之后在Python中清除元组

1 个答案: