Databases and python

[Dan Stromberg]

On Fri, 17 Feb 2006 12:32:52 +0100, Rene Pijlman wrote:

> Dan Stromberg:
>>> My first attempt would be: a BTree with the word as key, and a 'list of
>>> filenames' as value.
>>> http://www.zope.org/Wikis/ZODB/FrontPage/guide/node6.html#SECTION000630000000000000000
>>
>>This is basically what I'm doing now, 
> 
> Right. My second attempt would be: a BTree with the word as key, and a
> BTree of filenames as value (or some other persistent container type
> that's not (un)serialized as a whole when only one element changes).

This is a fantastic mapping from the problem domain to the solution
domain, but...  I don't know how to do a btree of btrees in python...  Nor
any other database of databases.

Would ZODB let me do that?

I'm puzzled, because:

strombrg at blee:~$ python
Python 2.4.2 (#2, Sep 30 2005, 21:19:01)
[GCC 4.0.2 20050808 (prerelease) (Ubuntu 4.0.1-4ubuntu8)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> d1={}
>>> d={}
>>> d[d1] = ''
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: dict objects are unhashable
>>>

Would I have to come up with some sort of hashable dict first?