django-raw-sugar 0.1.14

Turns your raw sql into a QuerySet

django-raw-sugar

Turns your raw sql into a QuerySet.

Installation

Install using pip...

pip install django-raw-sugar

How to use

Basic usage

Attach RawManager instance to your model. Then use it's .from_raw() method.

RawManager.from_raw(raw_query=None, params=None, translations=None, null_fields=None, db_table=None)

You should pass at least either raw_query or db_table (but not both).

# models.py
from django.db import models
from raw_sugar import RawManager

class MySimpleModel(models.Model):
    name = models.TextField()
    number = models.IntegerField()
    source = models.ForeignKey(AnotherSimpleModel, models.DO_NOTHING)

    objects = RawManager()

# some other file
from .models import MySimpleModel

queryset = MySimpleModel.objects.from_raw(
    'SELECT Null as id, "my str" as name, 111 as number, Null as source_id')

The queried table must contain all the fields that are present in target model, including primary key and foreign keys. If you know your query lacks some fields, you can provide the null_fields argument instead of modifying your query:

queryset = MySimpleModel.objects.from_raw(
    'SELECT "my str" as name, 111 as number', null_fields=['id', 'source_id'])

The resulting queryset is a regular models.QuerySet instance, and can be handled accordingly:

queryset = queryset.filter(number__gte=10)\
    .exclude(number__gte=1000)\
    .filter(name__contains='s')\
    .order_by('number')\
    .select_related('source')
print(queryset[0].name) # "my str"

Passing parameters

If you need to perform parameterized queries, you can use the params argument:

queryset = MySimpleModel.objects.from_raw(
    'SELECT "%s" as name, 111 as number', 
    params=['my str'],
    null_fields=['id', 'source_id'])

Using transtalions

If the field names of queried table differ from the model field names, you can map fields using the translations argument:

queryset = MySimpleModel.objects.from_raw(
    'SELECT "%s" as name, 111 as inner_number', 
    params=['my str'],
    translations={'inner_number': 'number'},
    null_fields=['id', 'source_id'])

Default raw sql

You can define a model manager that uses your raw sql as query source by default. You can do this by passing a from_raw argument to RawManager, or by using the raw_manager decorator to method that returns a FromRaw instance:

from django.db import models
from raw_sugar import raw_manager, RawManager, FromRaw

class MySimpleModel(models.model):
    name = models.TextField()
    number = models.IntegerField()
    source = models.ForeignKey(AnotherSimpleModel, models.DO_NOTHING)

    my_raw_manager = RawManager(FromRaw('SELECT "my str" as name, 111 as number',
                                        null_fields=['id', 'source_id']))

    @raw_manager
    def my_raw_manager_2(cls):
        return FromRaw('SELECT "my str" as name, 111 as number',
                       null_fields=['id', 'source_id'])

    @raw_manager(is_callable=True)
    def my_callable_raw_manager(cls, name=""):
        return FromRaw('SELECT %s as name, 111 as number',
                       null_fields=['id', 'source_id'],
                       params=[name])

# some other file
from .models import MySimpleModel

queryset = MySimpleModel.my_raw_source.all()
queryset = MySimpleModel.my_raw_source_2.all()
queryset = MySimpleModel.my_callable_raw_source('my str').all()

print(queryset[0].name) # "my str"

The FromRaw class accepts all the arguments as the RawManager.from_raw:

FromRaw(raw_query=None, params=None, translations=None, null_fields=None, db_table=None)

Querying views / table functions

If you have a sql view or a sql table function in your database and want to query it, instead of passing sql like SELECT * from my_view you can use the db_table argument instead:

queryset = MySimpleModel.objects.from_raw(db_table='my_view')
queryset = MySimpleModel.objects.from_raw(db_table='my_func(%s, %s)', params=['param', 1])

Differences with Manager.raw()

Pros:

• The result of executing of your raw sql is a QuerySet (!!!), and can filter, order, union, etc. it.

Cons:

• Your raw sql must contain all fields of target model, including foreign keys. If you'll omit one, you get an OperationalError('no such column: ...')
• If you queried Null as the value of a field, this field won't be queried when accessing it from the model instance.