python – 使用SELECT的sqlite准备语句

我正在开展一个小型宠物项目,该项目组织人们的漫画书并在SQL数据库中存储关于它们的元数据.为了正确起见,我使用预处理语句而不是
Python内置的字符串运算符,但我无法让它正常工作.这是我用来说明我遇到的问题的简短代码片段:

#!/usr/bin/env python

import sqlite3

connection = sqlite3.connect("MyComicBox.db")

curs = connection.cursor()

curs.execute("CREATE TABLE IF NOT EXISTS comic_collection (id INTEGER PRIMARY KEY, series TEXT, publisher TEXT, issue TEXT, tags TEXT)")

connection.commit()

def addComic(series = "", publisher = "", issue = "", tags = ""):
    curs.execute("INSERT INTO comic_collection (series, publisher, issue, tags) VALUES(?, ?, ?, ?)", (series, publisher, issue, tags))
    connection.commit()

def search(attribute, val):
    """
    Do an SQL query for all comics where attribute LIKE val and return a list of them.
    """

#   cmd = "SELECT * from comic_collection WHERE %s LIKE '%s'" % (attribute, val)
#   curs.execute(cmd)

    cmd = "SELECT * from comic_collection WHERE ? LIKE ?"
    curs.execute(cmd, (attribute, val))

    results = []

    for comic in curs:
        results.append(comic)

    return results

addComic(series = "Invincible Iron Man", issue = "500", publisher = "Marvel Comics", tags = "Iron Man; Spider-Man; Mandarin")


searchResults = search("issue", "500")

for item in searchResults:
    print item

我的问题在于搜索功能.查询不会返回任何内容,除非我替换我执行cmd的两行使用?运算符有两条(已注释掉的)行,我使用Python的内置字符串运算符执行cmd.任何人都可以帮我弄清楚我做错了什么?

最佳答案 您对属性的使用是错误的.想象一下?已包括其趋势.

一种方法是这样做:

cmd = "SELECT * from comic_collection WHERE %s LIKE ?" % attribute
curs.execute(cmd, val)

但是你必须确保属性不是来自不受信任的来源,或者它只有有效值,可能是

assert attribute in ('series', 'publisher', 'issue', 'tags')
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