How to fetch data from different tables in Django?

Question

I am new to Django and Python,

I have a table for clients, and one for trips. I can display the clients on the clients page, and the same for the trips.

But on the clients page, I want to show all the trips that are linked to each client. And this is where I hit a wall.

This is my models.py

from django.db import models
from django.core.validators import RegexValidator


# Create your models here.

class Clientes(models.Model):
    nome = models.CharField(max_length=30)
    apelido = models.CharField(max_length=30)
    morada = models.CharField(max_length=200)
    tel = models.CharField(max_length=9, validators=[RegexValidator(r'^\d{1,10}$')])
    nif = models.CharField(max_length=9, validators=[RegexValidator(r'^\d{1,10}$')])

    def __str__(self):
        return "%s %s" % (self.nome, self.apelido)

    class Meta:
        verbose_name_plural = "Clientes"

class Viagem(models.Model):
    trip_id = models.CharField(max_length=30)
    cliente = models.ForeignKey(Clientes, on_delete=models.CASCADE)
    comp = models.CharField(max_length=30)
    data = models.DateField()
    destino = models.CharField(max_length=30)

    def __str__(self):
        return self.trip_id

    class Meta:
        verbose_name_plural = "Viagens"

This is my views.py

from django.shortcuts import render
from django.http import HttpResponse
from .models import Clientes, Viagem

# Create your views here.

def index(request):
    ls= Clientes.objects.all()    
    context = {'ls': ls}
    return render(request, "booking/home.html", context)

def cliente(request, id):
    ls= Clientes.objects.filter(id=id)
    context = {'ls': ls}
    return render(request, "booking/cliente.html", context)

def trip(request):
    ls= Viagem.objects.all()    
    context = {'ls': ls}
    return render(request, "booking/trip.html", context)

and this is the table on the home.html

    <table id="selector" class="table is-fullwidth is-hoverable">
    <thead>
      <tr>
        <th>Nome</th>
        <th>Apelido</th>
        <th>Morada</th>
        <th>Telemóvel</th>
        <th>NIF</th>
        <th>Viagens</th>
      </tr>
    </thead>
    <tbody>
        {% for ls in ls %}
      <tr>
        <td>{{ls.nome}}</td>
        <td>{{ls.apelido}}</td>
        <td>{{ls.morada}}</td>
        <td>{{ls.tel}}</td>
        <td>{{ls.nif}}</td>
        <td>{{ls.trip_id}}</td>
      </tr>
      {% endfor %} 
    </tbody>
</table>

I assume it has something to do with ForeignKey, but a ForeignKey on the first class won't work.

I thought about creating a new def on the views.py using the Viagem table and a diferent context, but that also doesn't seem to be the solution.

So, anyone can point me in the right direction?

Answer 1

Since you are filtering by ID (fetching single object), this is one of the options to go:

views.py

from django.shortcuts import get_object_or_404

def cliente(request, id):
    ls = get_object_or_404(Clientes, id=id)
    trips = obj.viagem_set.all()
    context = {'ls': ls, 'trips': trips}
    return render(request, "booking/cliente.html", context)

template.html

<table id="selector" class="table is-fullwidth is-hoverable">
<thead>
  <tr>
    <th>Nome</th>
    <th>Apelido</th>
    <th>Morada</th>
    <th>Telemóvel</th>
    <th>NIF</th>
    <th>Viagens</th>
  </tr>
</thead>
<tbody>
  <tr>
    <td>{{ls.nome}}</td>
    <td>{{ls.apelido}}</td>
    <td>{{ls.morada}}</td>
    <td>{{ls.tel}}</td>
    <td>{{ls.nif}}</td>
    <td>{% for trip in trips %}{{ trip.id }}{% endfor %}</td>
  </tr>
  {% endfor %} 
</tbody>

While I'm not sure why you need to show record ID's in the table.

Answer 2

In your views.py , specifically the cliente function, you want to add the following line:

viagems=Viabem.objects.filter(cliente=ls)

modify the following line:

ls= Clientes.objects.filter(id=id)

so that it now shows:

ls=Clientes.objects.get(id=id)

and then change your context to equal:

context = {'ls': ls, 'viagems': viagems}

then you will be able to iterate over the different viagems in your html template file with the following kind of structure:

{% for viagem in viagems %}
  {{ viagem.whatever_field }}
{% endfor %}

and that should be it, I believe...

Answer 3

@João de Sousa, I found you want to show all trips that are associated with each client.

First of all you have to get a single client by his id obj = clients.objects.get(id = id) then this id pass to referred model like this obj1 = Viagem.objects.filter( id = obj.id)

According to my understanding from your above posted question is that you want to get help about how you get data from reference model/table. Django provides very easy and flexible way to get data from tables.

Feel free to ask any question if you need more clarification.