Why doesn't Django template show data correctly? - django

Question

I'm a new Django programmer and I'm writing a learning app. This app have a foreign key relations and I use prefetch_related method. This system runs well ;-)
My problem is at the template, when I show the data from the table, the browser shows this menssages:
ID Bill number Warehouse Article Quantity Price (<<-- columns)
1 CabeceraDeFacturas object (1) Primer almacén Bolsa plástico .05 mm. KK. 10 1
...
The questions are:
¿Why does show the message "CabeceraDeFacturas object (1)" instead of a bill number?
¿Can I fix this? ¿How?
The information about is:
Part of models.py
class CabeceraDeFacturas(models.Model):
ID_cliente = models.ForeignKey('Clientes',on_delete=models.CASCADE)
fecha_factura = models.DateField('Fecha de factura: ')
ID_formaDePago = models.ForeignKey('FormasDePago',on_delete=models.CASCADE)
Porcentaje_IVA = models.PositiveSmallIntegerField(default=21)
Total_factura = models.IntegerField()
class Meta:
ordering = ('id',)
#def __str__(self):
# return self.id
class LineasDeFacturacion(models.Model):
ID_factura = models.ForeignKey('CabeceraDeFacturas',on_delete=models.CASCADE)
ID_almacen = models.ForeignKey('Almacen',on_delete=models.CASCADE)
ID_articulo = models.ForeignKey('Articulos',on_delete=models.CASCADE)
cantidad = models.IntegerField(default=1)
Precio = models.IntegerField()
class Meta:
default_related_name = 'lineas'
# def __str__(self):
# return str(self.ID_factura)
Part of views.py
class VerFacturaCompleta(ListView):
#model = CabeceraDeFacturas
model = LineasDeFacturacion
template_name = "ListarTodasLasFacturasConLineas.html"
# recuperar las facturas completas y líneas --> comprobar
# queryset = CabeceraDeFacturas.objects.all().select_related('lineas')
queryset = LineasDeFacturacion.objects.all().prefetch_related('ID_factura')
paginate_by = 10
And finally, the template:
<h1>Listar facturas</h1>
<table class="table">
<thead>
<tr>
<th scope="col">ID</th>
<th scope="col">Factura</th>
<th scope ="col">Almacén</th>
<th scope ="col">Artículo</th>
<th scope ="col">Cantidad</th>
<th scope="col">Precio</th>
<!--<th scope="col">Almacén</th>-->
</tr>
</thead>
<tbody>
{% for articulo in object_list %}
<tr>
<!--<th scope="row">{{ articulo.pk }}</th>-->
<th scope ="row"> {{ articulo.pk }} </th>
<td>{{ articulo.ID_factura }}</td>
<td>{{ articulo.ID_almacen }}</td>
<td>{{ articulo.ID_articulo }}</td>
<td>{{ articulo.cantidad }}</td>
<td>{{ articulo.Precio }}</td>
</tr>
{% endfor %}
</tbody>
</table>
<hr>
Thanks a lot!

Answer 1

Well, the template only uses "object_list". This object_list comes form a instruction like this "queryset = LineasDeFacturacion.objects.all().prefetch_related('ID_factura')"; which is in a view.
The view which I use for this template is the next:
class VerFacturaCompleta(ListView):
#model = CabeceraDeFacturas
model = LineasDeFacturacion
template_name = "ListarTodasLasFacturasConLineas.html"
# recuperar las facturas completas y líneas --> comprobar
# queryset = CabeceraDeFacturas.objects.all().select_related('lineas')
queryset = LineasDeFacturacion.objects.all().prefetch_related('ID_factura')
paginate_by = 10
I don't use a context inside the view, only, the view pass an object_list (queryset) to the template.
Thanks for your time!

Answer 2

I found the mistake. The problem was in the models.py declaration. The CabeceraDeFactura class didn't had a data return. When I fixed this mistake
def __str__(self):
return str(self.id)
the template shows the data correctly.
Thanks for your time!