django query with …objects.raw

问题

How I can make a query with two models using this model.objects.raw(...)
and into the sql query has the INNER JOIN with the another model(table) this is possible

model.objects.raw('
SELECT     establecimiento.nombre, categoria.titulo
FROM         establecimiento INNER JOIN
                      categoria ON establecimiento.categoria = categoria.id')

I need print the establecimiento's name with his categoria's name

class Establecimiento(models.Model):
    nombre = models.CharField(max_length = 140)
    categoria = models.ForeignKey(Categoria)
    ciudad = models.ForeignKey(Ciudad)
    def __unicode__(self):
        return self.nombre



class Categoria(models.Model):
    titulo = models.CharField(max_length = 140)

回答1:

Fetching objects from the ORM automatically does any joins required and will return objects (instances of the models) which you can use to follow relationships.

If you simply fetch all your Establecimiento objects, you can access the related Categoria objects, like this:

all_objects = Establecimiento.objects.all()

for obj in all_objects:
   print('Number: {} Category: {}'.format(obj.nombre, obj.categoria.titulo))

Or, if you want to fetch only those two specific properties, use values, like this:

all_objects = Establecimiento.objects.values('nombre','ciudad__titulo')
for obj in all_objects:
   print('Number: {} Category: {}'.fromat(obj['nombre'],obj['ciudad__titulo']))

来源：https://stackoverflow.com/questions/21359710/django-query-with-objects-raw

标签

django

django-models

inner-join