README.md
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[Django](https://docs.djangoproject.com) model utilities for encouraging direct data access instead of unnecessary object overhead. Implemented through compatible method and operator extensions to `QuerySets` and `Managers`.
The goal is to provide elegant syntactic support for best practices in using Django's ORM. Specifically avoiding the inefficiencies and race conditions associated with always using objects.
## Usage
Typical model usage is verbose, inefficient, and incorrect.
```python
book = Book.objects.get(pk=pk)
book.rating = 5.0
book.save()
```
The correct method is generally supported, but arguably less readable.
```python
Book.objects.filter(pk=pk).update(rating=5.0)
```
`model_values` encourages the better approach with operator support.
```python
Book.objects[pk]['rating'] = 5.0
```
Similarly for queries:
```python
(book.rating for book in books)
books.values_list('rating', flat=True)
books['rating']
```
Column-oriented syntax is common in panel data layers, and the greater expressiveness cascades. `QuerySets` also support aggregation and conditionals.
```python
books.values_list('rating', flat=True).filter(rating__gt=0)
books['rating'] > 0
books.aggregate(models.Avg('rating'))['rating__avg']
books['rating'].mean()
```
`Managers` provide a variety of efficient primary key based utilities. To enable, instantiate the `Manager` in your models. As with any custom `Manager`, it doesn't have to be named `objects`, but it is designed to be a 100% compatible replacement.
```python
from model_values import Manager
class Book(models.Model):
...
objects = Manager()
```
`F` expressions are also enhanced, and can be used directly without model changes.
```python
from model_values import F
.filter(rating__gt=0, last_modified__range=(start, end))
.filter(F.rating > 0, F.last_modified.range(start, end))
```
## Installation
```console
% pip install django-model-values
```
## Tests
100% branch coverage.
```console
% pytest [--cov]
```