PyMySQL 和 OrderedDict [英] PyMySQL and OrderedDict

问题描述

我已经使用 PyMySQL 一段时间了，并创建了我自己的包装器，我习惯于速记编写查询.尽管如此，我一直在使用 OrderedDict 创建 CSV 文件，因为我需要保持顺序不变，但我意识到如果我使用 PyMySQL 查询数据库，我将无法获得数据库返回的顺序.如果我只想转储东西而不是手写订单，这对于抽查 CSV 文件来说有点烦人.

I've been using PyMySQL for a while now and created my own wrapper that I'm used to to shorthand writing queries. Nonetheless I've been creating CSV files with OrderedDict because I need to keep the order the same but I realize that if I use PyMySQL for querying the database, I will not get the order the database is giving back. This is a little annoying for spot checking CSV files if I wanted to just dump stuff rather than hand write the orders.

我的问题是，如何将 PyMySQL 与 OrderedDict 一起使用?目前我的代码如下:

My question is, how do I use PyMySQL with OrderedDict? Currently my code is as follows:

import pymysql
conn = pymysql.connect(host='localhost', user='root', passwd='', db='test')
cursor = conn.cursor(pymysql.cursors.DictCursor)

所以每当我查询时，我都会得到一本字典:

So whenever I query, I'll be getting a dictionary back:

cursor.execute("""SELECT * FROM test""")
for row in cursor:
    pp(row)  # gives me dictionary

我想要的是，当我滚动光标时，我实际上是按照列从数据库进入的顺序检索它们的 OrderedDict.

What I want is that when I roll through cursor I'm actually retrieving an OrderedDict of the columns in the order they come in from the database.

类似于:

cursor = conn.cursor(pymysql.cursors.OrderedDict)

推荐答案

您可以使用 cursors.DictCursorMixin 并将其 dict_type 更改为 collections.OrderedDict(默认为 dict):

You could use cursors.DictCursorMixin and change its dict_type to collections.OrderedDict (the default is dict):

from collections import OrderedDict
from pymysql.cursors import DictCursorMixin, Cursor

class OrderedDictCursor(DictCursorMixin, Cursor):
    dict_type = OrderedDict

然后就可以使用新的游标类了，如下图

Then you can use the new cursor class as shown below

cursor = conn.cursor(OrderedDictCursor)

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