创建pyodbc游标到多个数据库

Question

我正在使用pyodbc处理存储在MS-Access数据库中的事件。每个月都是一个单独的文件/数据库，我想处理多个月的事件。是否可以为包含多个月（即数据库连接）的视图创建游标？编辑1：无需编写新数据库？（也许有UNION VIEW之类的东西？）

Answer 1

您需要建立多个连接和游标，但是您应该能够处理数据。

比方说，该文件存储为month_1.mdb，month_2.mdb等，C:\access。

# Set up each connection, must have a way to access each file's name

connect_string = "Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=C:\\access\\month_{}.mdb;"

# Assuming that you'll get the same data from each database

sql = "SELECT column_1, column_2 FROM table"

# Connect to each file

connections = [pyodbc.connect(connect_string.format(n)) for n in range(1, 12 + 1)]

# Create a cursor for each file

cursors = [conn.cursor() for conn in connections]

# Query each file and save the data

data = []

for cur in cursors:

  cur.execute(sql)

  data.extend(cur.fetchall())

好的，现在您已经拥有了所有数据。您可以使用该sqlite3模块创建内存数据库，然后对其进行查询。

import sqlite3

# Create your temporary database

connection = sqlite3.connect(":memory:")

cursor = connection.cursor()

# Set up a place to hold the data fetched previously

_ = cur.execute("CREATE TABLE t(x INTEGER, y INTEGER)")

# Dump all the data into the database

for column_1, column_2 in data:

  _ = cursor.execute("INSERT INTO t VALUES (?, ?)", [column_1, column_2])

# Now you can run queries against the new view of your data