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https://github.com/paul-wolf/djaq

Django queries
https://github.com/paul-wolf/djaq

django-application django-models django-orm djaq-query query-language

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Django queries

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README

        

Djaq
====

|Python tests| |RTD build| |Python versions| |PyPi version|

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Djaq - pronounced “Jack” - is an alternative to the Django QuerySet API.

What sets it apart:

* No need to import models
* Clearer, more natural query syntax
* More powerful expressions
* More consistent query syntax without resorting to idiosyncratic methods like
``F()`` expressions, ``annotate()``, ``aggregate()``
* Column expressions are entirely evaluated in the database
* Extensible: you can write your own functions
* Pandas: Easily turn a query into Pandas Dataframe

There is also a JSON representation of queries, so you can send queries from a
client. It's an instant API to your data. No need to write backend classes and
serializers.

Djaq queries are strings. A query string for our example dataset might
look like this:

.. code:: shell

DQ("Book", "name as title, publisher.name as publisher").go()

This retrieves a list of book titles with book publisher. But you can
formulate far more sophisticated queries; see below. You can send Djaq
queries from any language, Java, Javascript, golang, etc. to a Django
application and get results as JSON. In contrast to REST frameworks,
like TastyPie or Django Rest Framework (DRF), you have natural access to
the Django ORM from the client.

Djaq sits on top of the Django ORM. It can happily be used alongside
QuerySets.

- `Documentation `__
- `Installation `__
- `Settings `__
- `Query
Usage `__
- `Sample
Project `__

Here's an example comparison between Djaq and Django QuerySets that gets every
publisher and counts the books for each that are above and below a rating
threshold.

.. code:: python

DQ("Book", """publisher.name,
sumif(rating < 3, 1, 0) as below_3,
sumif(rating >= 3, 1, 0) as above_3
""")

compared to QuerySet:

.. code:: python

from django.db.models import Count, Q
above_3 = Count('book', filter=Q(book__rating__gt=3))
below_3 = Count('book', filter=Q(book__rating__lte=3))
Publisher.objects.annotate(below_3=below_3).annotate(above_3=above_3)

Get average, maximum, minimum price of books:

.. code:: python

DQ("Book", "avg(price), max(price), min(price)")

compared to QuerySet:

.. code:: python

Book.objects.aggregate(Avg('price'), Max('price'), Min('price'))

Get the difference from the average off the maximum price for each publisher:

.. code:: python

DQ("Book", "publisher.name, max(price) - avg(price) as price_diff")

compared to QuerySet:

.. code:: python

from django.db.models import Avg, Max
Book.objects.values("publisher__name") \
.annotate(price_diff=Max('price') - Avg('price'))