SimpleDB

A Python 3 solution to the Simple Database Challenge

Usage

Interactive: python3 simpledb.py

With commands from file, 1 per line: python3 simpledb.py < commands.txt

Tests

SimpleDB uses pytest.

cd SimpleDB
./runtest.sh

Performance

Database updates (get, set, unset) as well as reference counting (numequalto) perform in O(1) time since these methods only read or modify a single value in each of a finite number of dictionaries. get and set may also append to a list in order to store transaction history, also in O(1).

O(M) memory will be used for each open transaction, where M is the number of values modified in the given transaction.

Possible Improvements

• get and set are misleading names since they also perform bookkeeping for transactions and reference counting. Extracting this logic using decorators or similar would improve readability and clarity.
• Using print statements produces correct output in the simplest way, but the API could be cleanly separated from the UI, by adding an additional layer of indirection in db_adapter which translates user input to SimpleDB commands. This would also allow choice of a different grammar for user commands.