Stefan Wójcik 50555ec73e
Better management of the automatic "_cls" field (#2112)
* Rename BaseQuerySet._initial_query to BaseQuerySet._cls_query

This new name more accurately reflects the purpose of the dict. It is either
empty for documents that don't use inheritance or it contains a `{"_cls": ...}`
shape query. There was nothing "initial" about it per se.

* Drop read_preference as a kwarg on BaseQuerySet.__call__/filter

It was a poor design choice to offer two different ways to do the same thing:
1. `SomeDoc.objects(foo=bar, bar=baz).read_preference(...)`
2. `SomeDoc.objects(foo=bar, bar=baz, read_preference=...)`

Option 1 is good because it's immediately obvious which part defines the query
to be used and which part defines the read preference.

Option 2 is bad because you don't immediately know whether `read_preference`
is a query kwarg or a reserved keyword with some special behavior. If you
wanted to be particularly cruel, you could even write
`SomeDoc.objects(foo=bar, read_preference=..., bar=baz)`.

THIS IS A BREAKING CHANGE. From now on you have to use the
`BaseQuerySet.read_preference(...)` method.

* Add a BaseQuerySet.clear_cls_query method + get rid of the class_check kwarg

This is similar to what the previous commit did to read preference except that
in this case we were still missing a `BaseQuerySet` method for clearing the
`_cls` query.

Now, instead of the undocumented, untested, and confusing interface:
    `ParentDoc.objects(foo=bar, bar=baz, class_check=False)`
We do:
    `ParentDoc.objects(foo=bar, bar=baz).clear_cls_query()`
2019-07-03 11:07:55 +02:00
2019-04-07 23:21:12 +03:00
2013-02-14 08:26:36 +00:00
2010-03-17 16:50:13 +00:00
2014-01-24 16:23:52 +00:00

===========
MongoEngine
===========
:Info: MongoEngine is an ORM-like layer on top of PyMongo.
:Repository: https://github.com/MongoEngine/mongoengine
:Author: Harry Marr (http://github.com/hmarr)
:Maintainer: Stefan Wójcik (http://github.com/wojcikstefan)

.. image:: https://travis-ci.org/MongoEngine/mongoengine.svg?branch=master
  :target: https://travis-ci.org/MongoEngine/mongoengine

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  :target: https://coveralls.io/github/MongoEngine/mongoengine?branch=master

.. image:: https://landscape.io/github/MongoEngine/mongoengine/master/landscape.svg?style=flat
  :target: https://landscape.io/github/MongoEngine/mongoengine/master
  :alt: Code Health

About
=====
MongoEngine is a Python Object-Document Mapper for working with MongoDB.
Documentation is available at https://mongoengine-odm.readthedocs.io - there
is currently a `tutorial <https://mongoengine-odm.readthedocs.io/tutorial.html>`_,
a `user guide <https://mongoengine-odm.readthedocs.io/guide/index.html>`_, and
an `API reference <https://mongoengine-odm.readthedocs.io/apireference.html>`_.

Supported MongoDB Versions
==========================
MongoEngine is currently tested against MongoDB v3.4 and v3.6. Future versions
should be supported as well, but aren't actively tested at the moment. Make
sure to open an issue or submit a pull request if you experience any problems
with MongoDB version > 3.6.

Installation
============
We recommend the use of `virtualenv <https://virtualenv.pypa.io/>`_ and of
`pip <https://pip.pypa.io/>`_. You can then use ``pip install -U mongoengine``.
You may also have `setuptools <http://peak.telecommunity.com/DevCenter/setuptools>`_
and thus you can use ``easy_install -U mongoengine``. Another option is
`pipenv <https://docs.pipenv.org/>`_. You can then use ``pipenv install mongoengine``
to both create the virtual environment and install the package. Otherwise, you can
download the source from `GitHub <http://github.com/MongoEngine/mongoengine>`_ and
run ``python setup.py install``.

Dependencies
============
All of the dependencies can easily be installed via `pip <https://pip.pypa.io/>`_.
At the very least, you'll need these two packages to use MongoEngine:

- pymongo>=3.4
- six>=1.10.0

If you utilize a ``DateTimeField``, you might also use a more flexible date parser:

- dateutil>=2.1.0

If you need to use an ``ImageField`` or ``ImageGridFsProxy``:

- Pillow>=2.0.0

Examples
========
Some simple examples of what MongoEngine code looks like:

.. code :: python

    from mongoengine import *
    connect('mydb')

    class BlogPost(Document):
        title = StringField(required=True, max_length=200)
        posted = DateTimeField(default=datetime.datetime.utcnow)
        tags = ListField(StringField(max_length=50))
        meta = {'allow_inheritance': True}

    class TextPost(BlogPost):
        content = StringField(required=True)

    class LinkPost(BlogPost):
        url = StringField(required=True)

    # Create a text-based post
    >>> post1 = TextPost(title='Using MongoEngine', content='See the tutorial')
    >>> post1.tags = ['mongodb', 'mongoengine']
    >>> post1.save()

    # Create a link-based post
    >>> post2 = LinkPost(title='MongoEngine Docs', url='hmarr.com/mongoengine')
    >>> post2.tags = ['mongoengine', 'documentation']
    >>> post2.save()

    # Iterate over all posts using the BlogPost superclass
    >>> for post in BlogPost.objects:
    ...     print '===', post.title, '==='
    ...     if isinstance(post, TextPost):
    ...         print post.content
    ...     elif isinstance(post, LinkPost):
    ...         print 'Link:', post.url
    ...     print
    ...

    # Count all blog posts and its subtypes
    >>> BlogPost.objects.count()
    2
    >>> TextPost.objects.count()
    1
    >>> LinkPost.objects.count()
    1

    # Count tagged posts
    >>> BlogPost.objects(tags='mongoengine').count()
    2
    >>> BlogPost.objects(tags='mongodb').count()
    1

Tests
=====
To run the test suite, ensure you are running a local instance of MongoDB on
the standard port and have ``nose`` installed. Then, run ``python setup.py nosetests``.

To run the test suite on every supported Python and PyMongo version, you can
use ``tox``. You'll need to make sure you have each supported Python version
installed in your environment and then:

.. code-block:: shell

    # Install tox
    $ pip install tox
    # Run the test suites
    $ tox

If you wish to run a subset of tests, use the nosetests convention:

.. code-block:: shell

    # Run all the tests in a particular test file
    $ python setup.py nosetests --tests tests/fields/fields.py
    # Run only particular test class in that file
    $ python setup.py nosetests --tests tests/fields/fields.py:FieldTest
    # Use the -s option if you want to print some debug statements or use pdb
    $ python setup.py nosetests --tests tests/fields/fields.py:FieldTest -s

Community
=========
- `MongoEngine Users mailing list
  <http://groups.google.com/group/mongoengine-users>`_
- `MongoEngine Developers mailing list
  <http://groups.google.com/group/mongoengine-dev>`_

Contributing
============
We welcome contributions! See the `Contribution guidelines <https://github.com/MongoEngine/mongoengine/blob/master/CONTRIBUTING.rst>`_
Description
A Python Object-Document-Mapper for working with MongoDB
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