Python DB that supports numbers

[Edward C. Jones]

Randall Hopper wrote:
> I'm looking for a very simple Python DB which supports:
> 
>      1) ints and floats as keys and values, 
>      2) performs DB access in the client, and 
>      3) stores the DB on disk.  
> 
> Just a simple DB for quick projects without the setup headache of
> server-based database systems.
> 
> For example, on the following table I just want to: "select * where
> column_1 is 1".  I'm using raw binary files now, but I'd prefer something
> more self-describing like an SQL table.
> 
>      1       10       1.814  177.1   13.61   73.2
>      1       5        1.624  182.5   -9999   -9999
>      1       2        1.259  185.9   13.24   73.9
>      2       10       2.672  181.4   13.59   72.5
>      2       5        2.423  183.2   -9999   -9999
>      2       2        1.902  190.7   13.27   73
>      3       10       3.208  181.9   13.46   72.1
>      3       5        2.787  186.6   -9999   -9999
>      3       2        2.17   194.7   13.16   72.3
> 
> Does anything like this exist in Python?

I would use a Python dictionary which I would store to disk using module 
cPickle.

     table = {}

     def AddRow(table, row):
         key = row[0]
         if not table.has_key(key):
         table[key] = []
         table[key].append(row)

     AddRow(table, [1, 10, 1.814, 177.1, 13.61, 73.2])
     AddRow(table, [1, 5, 1.624, 182.5, -9999, -9999])
     # ...
     AddRow(table, [3, 2, 2.17, 194.7, 13.16, 72.3])

     print table[1]

In the C++ Standard Template Library, there is a thing called a 
Multimap. It is like a Python dictionary except that each key can occur 
more than once. My Python name for this concept is "MultiDict". A 
MultiDict can be implemented in Python as a dictionary whose values are 
lists (like table[1] above). A MultiDict is a natural way to process 
sets of n-tuples.

I have attached MultiDict.py which I use when the approach above is too 
simple but MySQL is overkill.

Thanks,
Ed Jones
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