tinyble 0.1.4.5
A tiny NoSQL database with in-memory caching
License: MIT

Tinyble
=======

Introduction
------------
Tinyble is a super lightweight database inheriting `TinyDB`_. It is a document-oriented NoSQL but can also be used as a SQL database. It is most suitable for small applications where MongoDB is too way overkill.
The features are:

.. _TinyDB: https://github.com/msiemens/tinydb

- Written in pure Python and works well with most Python versions
- Very small, stored in JSON format and requires no external server
- Different from TinyDB, flexible auto-paging is provided to enable fast write-in and read-out
- Combine in-memory caching with disk storage to trade-off speed and reliability

Difference from TinyDB
----------------------
TinyDB stores each table in a single JSON file. For every IO operation, the JSON file will be wholly read and rewritten. As the file size gets larger or when there are many write-in operations, the speed can be dramatically slow.

Tinyble uses a separate thread to manage all the write/update operations. Specifically, all newly-updated data will first be stored in memory and an internal timer expires, they will be batch-written in the JSON file.

This reduces the number of IO operations. Moreover, a limit on the JSON file size is imposed when the size exceeds the limit, a new JSON file is created. This limits the volume of each read operation.

The internal timer and the file size can be set by users.


Version
-------
The latest version is v0.1.4. The current version is still on experimental status. Please use it with caution. Please contact me if you find any bugs/problems.

v0.1.4(07.03.2015)
^^^^^^^^^^^^^^^^^^
- added the close() function
- added the projection (partial search) function
- added the rst file


v0.1.3(04.03.2015)
^^^^^^^^^^^^^^^^^^
- fixed the print bug
- fixed the 'get' method bug

How to install
--------------
The easiest way to install is to use
::

    (sudo) pip install tinyble


in the command line tool.

Working with Django
-------------------
A very simple and ugly example showing the use of Tinyble with Django can be found in `Tinyble with Django`_

.. _Tinyble with Django: https://github.com/StevenSLXie/django_with_tinyble

Example
-------

Create a new database and a new collection
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

    db = Tinyble('data')
    collection = db.collection('example')

Insert some data
^^^^^^^^^^^^^^^^
::

    col = db.collection('example')

    col.insert({'type': 'apple', 'number': 1})
    col.insert({'type': 'pineapple', 'number': 2})
    col.insert({'type': 'blueberry', 'number': 3})

Update some data
^^^^^^^^^^^^^^^^
::

    col.update({'number':10}, cond= where('type')=='pineapple')



Delete some data
^^^^^^^^^^^^^^^^
::

    col.remove(eids=[3])
    col.remove(cond=where('number')<4)


Other usages are very similar to TinyDB.


Set the parameters
^^^^^^^^^^^^^^^^^^
::

    col.setting(file_size=100, query_cache_size=10, write_freq=5)


The above setting means each JSON file is limited to 100 entries and the database will store the latest 10 query results in memory and write-to-disk frequency is 5s.


Select some data
^^^^^^^^^^^^^^^^
::

    col.search(where('number')>2)

Select part of data in a document
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
::

    col.search(where('type')!= 'pineapple', ['number'])

This will only show the 'number' key, not the whole dictionary.