Question

Hey there, was wondering if anyone could help a newbie on SQL and Python. I thought I had a pretty decent grasp of it, however something odd happened recently.

Here is the the following code snipped from a larger portion:

  try:
      self.db.query("SELECT * FROM account WHERE email = '{0}' AND pass = '{1}'".format(self.mail.strip(self.bchars),self.pw.strip(self.bchars)))
  except MySQLdb.Error, e:
      print "Error %d: %s" % (e.args[0], e.args[1])

  exists = self.db.store_result().fetch_row()
  print "EXISTS",exists

It use to print this:

EXISTS ((2, '[e-mail]', '1234', 1, 0, 2161, '192.168.1.47', 0),)

Now, it prints this:
It use to print this:

EXISTS ((2L, '[e-mail]', '1234', 1L, 0L, 2161, '192.168.1.47', 0L),)

I have no idea where these L’s came from. I checked the SQL Database and even reloaded it to be sure. I have reverted all my code for the last day (where all was functioning), but still can’t find a solution. I have also tried searching, but I am not even sure what this problem is even called so it’s hard to search. Thanks for any help or information anyone can provide.

Answer 1

I think, python’s dbapi is supposed to always return integer-fields as long.

Anyway, 10L, 5L and so on is the way repr (which is used on every item of a tuple in your case) works for longs.

One more thing. I see, you are using MySQLdb. In that case, I strongly suggest, that you stop using the c-api wrapper, but instead use the “real” interface, that has all that automatic conversion/escaping and a bunch of other wonderful things (dict-cursors for one).

This will save you a lot of grief and WILL make your code more stable/secure. In short, just forget about _mysql. Trust me.

Your example can be rewritten as this (using the proper interface):

import MySQLdb

db = MySQLdb.connect(host=your_host, db=your_db,
                     user=your_user, passwd=your_password)

cur = db.cursor()
cur.execute("""SELECT * FROM account WHERE email = %s AND pass = %s """,
            (self.mail, self.pw))
result = cur.fetchall()
print "exists:", result

This does the same as you are doing (except the error handling), but without manual string-formatting, escaping and so on.

I know, this is going to be downvoted for irrelevance, probably, but if this answer helps even a single person to start using the proper database api, that would be really great.