bsddb for beginners?

[A.Newby]

I want to get into databases, but most of the tuts around seem to be over 
my head. 

For instance, looking through the standard Python documentation for bsddb 
module, 7.12 bsddb -- Interface to Berkeley DB library, doesn't really 
explain what all the syntax is for. For instance, this example ......

>>> import bsddb
>>> db = bsddb.btopen('spam.db', 'c')
>>> for i in range(10): db['%d'%i] = '%d'% (i*i)

....... obviously creates a database file which behaves a dictionary. If I 
type 

>>>db.keys()

... I get a complete a list of the dictionary's keys (0 - 9). But why? And 
how do I store values in those keys? What does the  "%" symbol mean, and 
what's it used for? 

So what homework do I need to do to understand this stuff?

Also, do I take it that the Berkely System comes with Python 2.2, and 
therefore I don't need to download anything else? Or is bsddb merely an 
interface for the Berkely System?

-- 
cdewin at dingoblue.net.au