I'm playing with querysets in django.
What I'm looking it's to save a new foreign product or item but I can not achieve it.
shell
from applaboratorio.models import Datos_empresa_DB, Datos_equipo_DB
detalle = Datos_empresa_DB.objects.filter(pk=58)
resp = Datos_equipo_DB(equipo='dell-labtop',marca='dell', modelo='432423',Foraneo_Datos_empresa_DB = detalle)
models.py
class Datos_empresa_DB(models.Model):
nombre = models.CharField(max_length=150)
empresa = models.CharField(max_length=150)
class Datos_equipo_DB(models.Model):
Foraneo_Datos_empresa_DB = models.ForeignKey(Datos_empresa_DB)
equipo = models.CharField(max_length=300)
marca = models.CharField(max_length=300)
modelo = models.CharField(max_length=300)
What am I doing bad?
I'm trying to create a new product for a client that already exist in db.
I think you're nearly there. You need to call the save method of the new product to save to the DB, and to retrieve the related client object, you should get not filter so you have the object itself and not a list of objects (or QuerySet):
detalle = Datos_empresa_DB.objects.get(pk=58)
# ^^^
resp = Datos_equipo_DB(equipo='dell-labtop',marca='dell', modelo='432423',Foraneo_Datos_empresa_DB =detalle)
# Save on model's related field <-^^^^^^^
resp.save()
Related
I am working with Django and REST Framework and I am trying to create a get function for one of my Views and running into an error. The basic idea is that I am creating a market which can have multiple shops. For each shop there can be many products. So, I am trying to query all those products which exist in one shop. Once I get all those products I want to send it to my serializer which will finally return it as a JSON object. I have been able to make it work for one product but it does not work for an array of products.
My Product model looks like this:
'''Product model to store the details of all the products'''
class Product(models.Model):
# Define the fields of the product model
name = models.CharField(max_length=100)
price = models.IntegerField(default=0)
quantity = models.IntegerField(default=0)
description = models.CharField(max_length=200, default='', null=True, blank=True)
image = models.ImageField(upload_to='uploads/images/products')
category = models.ForeignKey(Category, on_delete=models.CASCADE, default=1) # Foriegn key with Category Model
store = models.ForeignKey(Store, on_delete=models.CASCADE, default=1)
''' Filter functions for the product model '''
# Create a static method to retrieve all products from the database
#staticmethod
def get_all_products():
# Return all products
return Product.objects.all()
# Filter the data by store ID:
#staticmethod
def get_all_products_by_store(store_id):
# Check if store ID was passed
if store_id:
return Product.objects.filter(store=store_id)
The product serializer that I built is as follows:-
class ProductSerializer(serializers.ModelSerializer):
class Meta:
model = Product
fields = '__all__'
and the view that I created is below
class StoreView(generics.ListAPIView):
"""Store view which returns the store data as a Json file.
"""
# Define class variables
serializer_class = StoreSerializer
# Manage a get request
def get(self, request):
# Get storeid for filtering from the page
store_id = request.GET.get('id')
if store_id:
queryset = Product.get_all_products_by_store(store_id)
# queryset = Product.get_all_products_by_store(store_id)[0]
else:
queryset = Product.get_all_products()
# queryset = Product.get_all_products()[0]
print("QUERYSET", queryset)
return Response(ProductSerializer(queryset).data)
The above view gives me the following error
AttributeError at /market
Got AttributeError when attempting to get a value for field `name` on serializer `ProductSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `QuerySet` instance.
Original exception text was: 'QuerySet' object has no attribute 'name'.
If instead queryset = Product.get_all_products_by_store(store_id), I use the line below it where I am only selecting the first option then I get the correct JSON response but if there multiple products then I am not able to serialize. How do I make it work?
If you want to serialize more than one record, either use ListSerializer instead, or pass many=True the the constructor of ModelSerializer:
return Response(ProductSerializer(queryset, many=True).data)
I found the answer thanks to #yedpodtrzitko for giving the direction.
I had to make two changes.
Define queryset outside the function
Pass many=True the the constructor of ModelSerializer
class StoreView(generics.ListAPIView):
"""Store view which returns the store data as a Json file.
"""
# Define class variables
queryset = []
serializer_class = StoreSerializer
# Manage a get request
def get(self, request):
# Get storeid for filtering from the page
store_id = request.GET.get('id')
if store_id:
queryset = Product.get_all_products_by_store(store_id)
else:
queryset = Product.get_all_products()
print("QUERYSET", queryset)
return Response(ProductSerializer(queryset, many = True).data)
I want to duplicate an attribute from other class.
class PedidoCliente(Pedido):
total_pagado = models.DecimalField(blank=True, max_digits=10, decimal_places=2,default = 0,verbose_name="Pagado $") # default 0 para el error for += int
barril_encargado = models.DecimalField(blank=True, default=0, max_digits=10, decimal_places=2,verbose_name="Barr. entregados")
fecha_entrega = models.DateField(verbose_name="Fecha Entrega")
class DetallePedidoCliente(DetallePedido):
comments = models.CharField(max_length=300, verbose_name="Comentarios")
precio_venta = models.DecimalField(max_digits=16, decimal_places=2, default = 0)
pedido = models.ForeignKey(PedidoCliente,on_delete=models.CASCADE)
fecha_entrega = the same from PedidoCliente
I'm new at OPP so sorry if it's a silly question.
Thanks!
One should not look to mirror fields of another model. This simply leads to extra work. One needs to update this mirrored field each time it is updated in the other table, etc.
Also it is not very useful when we have already cemented the relationship between the two tables using a Foreign Key.
To access a related fields data is very easy in Django. Suppose we have an instance of DetallePedidoCliente named instance using this we can access the fecha_entrega of the related model by the foreign key as follows:
instance.pedido.fecha_entrega
If one just wants an easy way to refer to this field one may consider adding a property to the model:
class DetallePedidoCliente(DetallePedido):
comments = models.CharField(max_length=300, verbose_name="Comentarios")
precio_venta = models.DecimalField(max_digits=16, decimal_places=2, default = 0)
pedido = models.ForeignKey(PedidoCliente,on_delete=models.CASCADE)
#property
def fecha_entrega(self):
return self.pedido.fecha_entrega
Now we can simply access the field as:
instance.fecha_entrega
I have a Django model with a GenericForeignKey, and several other models pointing to it through GenericRelation:
class InventoryAction(CustomModel):
action_content_type = models.ForeignKey(ContentType, on_delete=models.PROTECT,limit_choices_to={'model__in': ('inventoryinput', 'inventorytransfer', 'inventoryadjustment', 'physicalinventory', 'requisition', 'sale', 'inventorysalecancellation', 'inventorystockinit')}, related_name='inventory_actions', verbose_name=_("Tipo de Acción"))
action_object_id = models.PositiveIntegerField(verbose_name=_("ID de la acción"))
action_object = GenericForeignKey('action_content_type', 'action_object_id')
timestamp = models.DateTimeField(auto_now=True, verbose_name=_("Fecha y hora"))
class InventoryStockInit(CustomModel):
repository = models.ForeignKey(Repository, on_delete=models.PROTECT, related_name='stock_init', verbose_name=_("Almacén"))
timestamp = models.DateTimeField(auto_now=True, verbose_name=_("Fecha y Hora"))
comments = models.TextField(null=True, blank=True, verbose_name=_("Comentarios"))
inventory_action = GenericRelation(InventoryAction, content_type_field='action_content_type', object_id_field='action_object_id')
class InventoryInput(CustomModel):
repository = models.ForeignKey(Repository, on_delete=models.PROTECT, related_name='inputs', verbose_name=_("Almacén"))
reference = models.ForeignKey(InventoryAction, null=True, blank=True, on_delete=models.PROTECT, limit_choices_to=Q(action_content_type__model__in=['inventorytransfer', ]), related_name='referenced_by', verbose_name=_("Referencia"))
inventory_action = GenericRelation(InventoryAction, content_type_field='action_content_type', object_id_field='action_object_id')
And I have a Django Rest Framework viewset that attempts to get all related records from the GenericForeignKey:
class InventoryActionForListViewSet(viewsets.ViewSet):
permission_classes = (permissions.IsAuthenticated,)
def list(self, request):
self.repository = request.query_params['repository']
inventory_actions = models.InventoryAction.objects.filter(inventory_action__repository_id=self.repository).order_by('-timestamp')
inventory_actions_to_return = serializers.InventoryActionForListSerializer(inventory_actions, many=True)
return Response(inventory_actions_to_return)
The problem is that the view raises the following exception:
django.core.exceptions.FieldError: Cannot resolve keyword 'inventory_action' into field. Choices are: action_content_type, action_content_type_id, action_object, action_object_id, batch, id, products, referenced_by, referenced_by_input_or_output, referenced_by_output, timestamp
I can see that the GenericRelation is not being recognized. how can I execute the query I want, using generic relationships?
inventory_action is a field on your InventoryStockInit and InventoryInput models - you can't expect it to be a field in your InventoryAction model.
With the relation you defined, each of your InventoryAction objects can be related to a single object in one of he models stated in limit_choices_to. There is only one object related to a single InventoryAction. You can access it by accessing action object, for example:
inventory_action = InventoryAction.objects.first()
inventory_action.action_object # this will be a single object of one of the models in limit_choices_to.
Your InventoryInput model on the other hand can be pointed by multiple inventory actions. To see which inventory actions are pointing to a particular InventoryInput object, you can do:
inventory_input = InventoryInput.objects.first()
inventory_input.inventory_action.all()
As you can see, inventory_action is a manager of all related objects, it would be better to call it inventory_actions (plural). I think what you might be trying to achieve is a reverse relation (single InventoryAction object referenced by multiple objects of other models).
I want to fetch and display details(name_project, user_name) from both tables Project and User1
models.py
class Project(models.Model):
name_project = models.CharField(max_length=50)
leader = models.ForeignKey('User1', default='')
category_project = models.CharField(max_length=50)
class User1(models.Model):
user_name = models.CharField(max_length=30)
mail = models.EmailField(max_length=50)
password = models.CharField(max_length=50)
views.py
def list_project(request):
queryset = Project.objects.raw(
'SELECT scrum_rest_project.id, scrum_rest_project.name_project, scrum_rest_user1.user_name FROM scrum_rest_user1,scrum_rest_project WHERE scrum_rest_user1.id = scrum_rest_project.leader_id')
queryset = serializers.serialize('json', queryset)
return HttpResponse(queryset, content_type="application/json")
but it displays only data from Project table in the json file, I want to display data from User1 table also
You should use select related feature :
Project.objects.select_related().all()
Why are you using raw SQL? Learn Querysets.
1. Using Querysets:
projects = Project.objects.select_related('leader').all()
for project in projects:
print project.name, project.leader.user_name
Note: select_related creates join with User1 and saves you extra SQL queries when accessing User1 model
2. get only list of leader and project name.
project_list = Project.objects.select_related('leader')\
.values_list('name', 'leader__user_name')
I'm writing an app that has an HTML page which must be capable of saving data into 2 models. I've created two separate forms and referenced them in the view, however the information is not saving into the DB.
Here are the views.py
def nuevoingreso(request):
if request.method == "POST":
formingreso = NuevoIngreso(request.POST)
formprodingreso = NuevoProdIngreso(request.POST)
if formingreso.is_valid():
ingreso = formingreso.save(commit=False)
ingreso.idUser = request.user
ingreso.Condominio = get_object_or_404(Condominios, idCondominio=request.session["idCondominio"])
ingreso.save()
ingresoprod = formprodingreso.save()
for i in range(5):
if ProductosIngresos.SubtotalP != "" and ProductosIngresos.IvaP != "" and ProductosIngresos.TotalP != "":
ingresoprod.ProductosIngresos(Concepto=request.POST.get("Concepto"+str(i), ""), SubtotalP=request.POST.get("SubtotalP"+str(i), ""), IvaP=request.POST.get("IvaP"+str(i), ""), TotalP=request.POST.get("TotalP"+str(i), ""))
ingresoprod.save()
return HttpResponseRedirect("/propiedades/")
else:
return render(request, "immovelc/nuevoingreso.html",
{"formingreso": formingreso, "formprodingreso": formprodingreso})
propiedadesing = PropiedadesCond.objects.all()
context = ({"propiedadesing": propiedadesing})
return render(request, "immovelc/nuevoingreso.html", context)
forms.py
class NuevoIngreso(ModelForm):
class Meta:
model = Ingresos
fields = ["Numero", "Persona", "Fecha", "Observaciones", "Cobrado", "Subtotal", "Iva", "Total"]
def clean(self):
Numero = self.cleaned_data["Numero"]
Persona = self.cleaned_data["Persona"]
Fecha = self.cleaned_data["Fecha"]
if not Numero:
raise forms.ValidationError("El campo de numero es obligatorio")
if not Persona:
raise forms.ValidationError("El campo de cliente es obligatorio")
if not Fecha:
raise forms.ValidationError("El campo de fecha es obligatorio")
class NuevoProdIngreso(ModelForm):
class Meta:
model = ProductosIngresos
fields = ["Concepto", "SubtotalP", "IvaP", "TotalP"]
models.py
class Ingresos(models.Model):
idIngreso = models.AutoField(primary_key=True, null=False, max_length=15)
idCondominio = models.ForeignKey(Condominios)
idUser = models.ForeignKey(User)
Numero = models.CharField(max_length=100)
Persona = models.CharField(max_length=250, default="Ninguno")
Cobrado = models.CharField(max_length=100, default=0)
Observaciones = models.TextField(default="Ninguna")
Fecha = models.DateField()
Subtotal = models.CharField(max_length=100)
Iva = models.CharField(max_length=100)
Total = models.CharField(max_length=100)
def __unicode__(self):
return unicode(self.idIngreso)
class ProductosIngresos(models.Model):
idProductoIngreso = models.AutoField(primary_key=True, null=False, max_length=15)
idIngreso = models.ForeignKey(Ingresos)
Concepto = models.CharField(max_length=500)
SubtotalP = models.CharField(max_length=100)
IvaP = models.CharField(max_length=100)
TotalP = models.CharField(max_length=100)
def __unicode__(self):
return unicode(self.idProductoIngreso)
Thanks!
No offence, but this code is far from being correct.
Besides you've got many errors that you might want to remove.
Errors:
formprodingreso.is_valid() is never called
inside for i in range(5) you use a class as if it was an instance (ProductosIngresos.SubtotalP)
clean method in form has to be outside the Meta block
I believe what you want inside the loop is:
producto_ingreso = ProductosIngresos()
producto_ingreso.idIngreso = ingreso # better change to producto_ingreso.ingreso
producto_ingreso.Concepto=request.POST.get("Concepto"+str(i), "") # producto_ingreso.concepto
producto_ingreso.SubtotalP=request.POST.get("SubtotalP"+str(i), "") # producto_ingreso.subtotal_p
producto_ingreso.IvaP=request.POST.get("IvaP"+str(i), "")
producto_ingreso.TotalP=request.POST.get("TotalP"+str(i), ""))
producto_ingreso.save()
To make it cleaner, you can make this king of logic overridding the save() method of ModelForm. Or use inline formsets.
Confusion:
Model FKs are objects in Django, not integers. Better name them like condominio instead of idCondominio
Decimal columns (subtotal, iva, total) should be declared as deciaml i.e. models.DecimalField(max_digits=10, decimal_places=2)
clean method is intended for cross field validation (more than one field). Only one field should be validated by clean_numero f.e.
Over complication:
models have ID/PK by default, no need to explicit them (referenced as self.id or self.pk)
model unicode function is not giving any info
clean and ValidationError are superflous: modelform checks if attributes are requiered automatically
Convention errors:
attributes are always written_in_lowercase (SubtotalP -> subtotal_p)
I would seriously try to fix all of those if you dont want the developers maintaining your code hate you and make some voodoo on you.