Tinydb

^^^^^^^^^^^^^^^^^^^

- Feature: Add a no-op query ``Query().noop()`` (see
`issue 313 <https://github.com/msiemens/tinydb/issues/313>`_)
- Feature: Add a ``access_mode`` flag to ``JSONStorage`` to allow opening
files read-only (see `issue 297 <https://github.com/msiemens/tinydb/issues/297>`_)
- Fix: Don't drop the first document that's being inserted when inserting
data on an existing database (see `issue 314
<https://github.com/msiemens/tinydb/issues/314>`_)

^^^^^^^^^^^^^^^^^^^

:ref:`Upgrade Notes <upgrade_v4_0>`

Breaking Changes
----------------

- Python 2 support has been removed, see `issue 284
<https://github.com/msiemens/tinydb/issues/284>`_
for background
- API changes:

- Removed classes: ``DataProxy``, ``StorageProxy``
- Attributes removed from ``TinyDB`` in favor of
customizing ``TinyDB``'s behavior by subclassing it and overloading
``__init__(...)`` and ``table(...)``:

- ``DEFAULT_TABLE``
- ``DEFAULT_TABLE_KWARGS``
- ``DEFAULT_STORAGE``

- Arguments removed from ``TinyDB(...)``:

- ``default_table``: replace with ``TinyDB.default_table_name = 'name'``
- ``table_class``: replace with ``TinyDB.table_class = Class``

- ``TinyDB.contains(...)``'s ``doc_ids`` parameter has been renamed to
``doc_id`` and now only takes a single document ID
- ``TinyDB.purge_tables(...)`` has been renamed to ``TinyDB.drop_tables(...)``
- ``TinyDB.purge_table(...)`` has been renamed to ``TinyDB.drop_table(...)``
- ``TinyDB.write_back(...)`` has been removed
- ``TinyDB.process_elements(...)`` has been removed
- ``Table.purge()`` has been renamed to ``Table.truncate()``
- Evaluating an empty ``Query()`` without any test operators will now result
in an exception, use ``Query().noop()`` (introduced in v4.1.0) instead

- ``ujson`` support has been removed, see `issue 263
<https://github.com/msiemens/tinydb/issues/263>`_ and `issue 306
<https://github.com/msiemens/tinydb/issues/306>`_ for background
- The deprecated Element ID API has been removed (e.g. using the ``Element``
class or ``eids`` parameter) in favor the Document API, see
`pull request 158 <https://github.com/msiemens/tinydb/pull/158>`_ for details
on the replacement

Improvements
------------

- TinyDB's internal architecture has been reworked to be more simple and
streamlined in order to make it easier to customize TinyDB's behavior
- With the new architecture, TinyDB performance will improve for many
applications

Bugfixes
--------

- Don't break the tests when ``ujson`` is installed (see `issue 262
<https://github.com/msiemens/tinydb/issues/262>`_)
- Fix performance when reading data (see `issue 250
<https://github.com/msiemens/tinydb/issues/250>`_)
- Fix inconsistent purge function names (see `issue 103
<https://github.com/msiemens/tinydb/issues/103>`_)

^^^^^^^^^^^^^^^^^^^^

- Internal change: fix missing values handling for ``LRUCache``

^^^^^^^^^^^^^^^^^^^^

- Feature: allow setting the parameters of TinyDB's default table
(see `issue 278 <https://github.com/msiemens/tinydb/issues/278>`_)

^^^^^^^^^^^^^^^^^^^^

- Internal change: support correct iteration for ``LRUCache`` objects

^^^^^^^^^^^^^^^^^^^^

- Internal change: fix Query class to permit subclass creation
(see `pull request 270 <https://github.com/msiemens/tinydb/pull/270>`_)