我有一個寫入數據庫的方法,用戶名和密碼的用戶誰希望註冊。在存儲他們提供給數據庫的用戶名和密碼之前,我想檢查他們選擇的用戶名是否已經存在於「未決」列表或已批准的「聯繫人」列表中。Python和SQLite:檢查數據庫中是否存在項目?
這裏是我以前做的代碼:
@cherrypy.expose
def writePending(self, username=None, password=None, message=None, signin=None):
""" Add request of friendship into a database which stores all
pending friendships.
"""
page = get_file(staticfolder + "/html/friendingPage.html")
if username != "" and password != "" and message !="":
con = lite.connect('static/database/Friendship.db')
cur = con.cursor()
with con:
cur.execute("CREATE TABLE IF NOT EXISTS pending(user TEXT, pass TEXT, info TEXT)")
cur.execute("CREATE TABLE IF NOT EXISTS contacts(user TEXT, pass TEXT)")
"Check to see if the username is already registered"
cur.execute("Select * from pending where user = ?", (username,))
check1=cur.fetchone()
cur.execute("Select * from contacts where user = ?", (username,))
check2=cur.fetchone()
if check1[0] != None:
page = page.replace("$Error", "The ID you used is still pending for friendship")
elif check2[0] != None:
page = page.replace("$Error", "The ID you used is already added as a contact")
else:
cur.execute("CREATE TABLE IF NOT EXISTS pending(user TEXT, pass TEXT, info TEXT)")
cur.execute("INSERT INTO pending VALUES(?, ?, ?)", (username, password, message))
page = get_file(staticfolder + "/html/thankYouPage.html")
else:
page = get_file(staticfolder + "/html/friendingPage.html")
page = page.replace("$Error", "You Must fill out all fields to proceed")
return page
不過,我會得到那個
Traceback (most recent call last):
File "/usr/lib/pymodules/python2.7/cherrypy/_cprequest.py", line 606, in respond
cherrypy.response.body = self.handler()
File "/usr/lib/pymodules/python2.7/cherrypy/_cpdispatch.py", line 25, in __call__
return self.callable(*self.args, **self.kwargs)
File "proj1base.py", line 540, in writePending
if type(check1[0]) != None:
TypeError: 'NoneType' object is not subscriptable
我想知道我能做些什麼,以避免消息?
謝謝。