执行许多混乱 [英] Executemany confusion

问题描述

好的，所以我有一个函数可以根据插件的输入在 sqlite 数据库中选择某些行.当只涉及一个语句时，我使用插件来选择和获取行，但由于我想为此增加一些灵活性，我尝试让函数在遇到列表或元组时使用 executemany.然而，尽管我已经摆弄和改变了所有的东西，我仍然无法让它工作，要么是因为 sqlite 语句将字符串中的每个字符视为绑定，要么是因为元组中有太多的绑定.这是我到目前为止的代码:

Ok, so I have a function that selects certain rows in a sqlite database based on input from a plugin. I got the plugin to select and fetch rows when just one statement is involved, but since I want to add some flexibility to this, I tried making the function use executemany when encountering lists or tuples. Yet, despite all the things I have fiddled and changed, I a still unable to get this to work, either because the sqlite statement is treating each character in the string as a binding, or because there are too many bindings in the tuple. Here's the code I have so far:

    def readoffset(self,offset):
        vartype = type(name)
        print(vartype)
        if vartype == int:
            self.memcursor.execute('''select all id,matbefore,matafter,name,date 
                                   from main as main where id = ?''',[offset])
            undolist = self.memcursor.fetchall()
            print(undolist)
            return(undolist)
        elif vartype == tuple or list:
            print(vartype)
            self.memcursor.executemany('''select all id,matbefore,matafter,name,date 
                                       from main as main where name = (?)''', [offset])
            undolist = self.memcursor.fetchall()
            return(undolist)

推荐答案

看http://www.python.org/dev/peps/pep-0249/

使用此方法进行操作产生一个或更多的结果集构成未定义的行为，并且允许实施

Use of this method for an operation which produces one or more result sets constitutes undefined behavior, and the implementation is permitted

因此，executemany 可用于 INSERT 和 UPDATE 但不能用于 SELECT

So, executemany can be used for INSERT's and UPDATE's but not for SELECT

您可以尝试以下代码:

elif isinstance(offset, (tuple, list)):
    offsets=', '.join(offset)
    self.memcursor.execute('''select all id,matbefore,matafter,name,date 
                                       from main as main where name IN (?)''', [offsets])

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