bsddb.btopen()

Anthony McDonald tonym1972/at/club-internet/in/fr
Wed Aug 13 12:38:07 CEST 2003


PythonWin 2.3 (#46, Jul 29 2003, 18:54:32) [MSC v.1200 32 bit (Intel)] on
win32.
Portions Copyright 1994-2001 Mark Hammond (mhammond at skippinet.com.au) - see
'Help/About PythonWin' for further copyright information.
>>> import os
>>> import bsddb
>>> os.chdir("c:/test")
>>> my_data = bsddb.btopen("testing", 'c')
>>> for i in range(10):
...  if i == 5:
...   pass
...  else:
...   my_data['%d'%i] = '%d'% (i*i)
...
>>> my_data.keys()
['0', '1', '2', '3', '4', '6', '7', '8', '9']
>>> my_data.sync()

Now heres where my problem is.

The documentation explicitly states that a btopen database when asked to
locate a key that doesn't exist in the dataset, will return the next sorted
key from the dataset.

So my_data.set_location('5') should return as if I'd called
my_data.set_location('6')
>>> my_data.set_location('5')
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
  File "C:\Python23\lib\bsddb\__init__.py", line 117, in set_location
    return self.dbc.set(key)
DBNotFoundError: (-30991, 'DB_NOTFOUND: No matching key/data pair found')

Okay maybe it has positioned the cursor, but is just raising the exception
to politely tell me that I'm not pointing at the key I asked for. So
my_data.previous() will return the key/data pair for key "4".

>>> my_data.previous()
('9', '81')

Okay its pointing at the end of the database. Erm thats not as advertised.

Okay whats broken? Is the documentation wrong? Is my version of Python
wrong?, or do I need to drink some more coffee?

TonyM






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