Django - How to Retrieve Data in Database in Dropdownlist

retrive data according to the dropdown list item selected, in django

This Question Helped me a lot in creating the logic for this problem.
[Django]How to return value to view after select item from dropdown list

views.py

from django.shortcuts import render
from range.models import price_range

def showobj(request):
    selected_range = None
    range_price = price_range.objects.all()

    if request.method == "POST":
       
        selected_range = request.POST.get("range")
        range_price = range_price.filter(name=selected_range)

    
    price = price_range.objects.order_by('name').values_list('name', flat=True)

    context = {
        'ranges': price,
        'range_price': range_price,
        'selected_range': selected_range,
    }

    return render(request, 'range/price_range.html', context)

---

price_range.html

<center>
<h1>Index</h1>
    <form method="post">
    {% csrf_token %}
 {% if selected_range %}
       {% for rest in range_price %}
      <input name="price_value" value="{{ rest.price }}"></input>
     {% endfor %}
{% endif %}
    <select name="range">
         <option selected disabled="true">Select the Price Range</option>
         {% for range in ranges %}
             <option value="{{ range }}" {% if selected_range == range %} selected="selected" {% endif %}>{{ range }}</option>
         {% endfor %}
    </select>
    <input type="submit" value="Select">

</form>
</center>

Django - Unable to retrieve data in database in dropdownlist

Try this, in your select

{% if paper %}
{% for p in paper %}
    <option value="{{ p.id }}">{{ p.year }} {{ p.month }} Paper {{ p.number }} </option>
{% endfor %}
{% endif %}

Also go through this tutorial, django tutorial part 3.

Also django models have a default primary key attribute you can use that also.

Select data from drop-down list and save it to database in Django

You can render choices using {% for %} loop and FoodStatus list of choices like this:

<td>
    {{ order.get_food_status_display }}
    <select name="food_status">
        {% for id, choice in order.FoodStatus %}
            <option value="{{ id }}"{% if order.food_status == id %} selected="selected"{% endif %}>{{ choice }}</option>
        {% endfor %}
    </select>
</td>

You can display actual status text (instead of id), using get_FOO_display method.

Added {% if %} tag to preselect correct option.

Consider switching to Forms so it can handle rendering fields automatically.(!!!)

Consider switching food_status to IntegerField instead. Provide default attribute, so it will always be one of the choices, even if not specified.

Get data from dropdown list and display it in the form of table

In your views.py:

def save_machine(request):
   if request.method == "POST":
      machine_name = request.POST.get('machine_name','')
      operation_no = request.POST.get('operation_no','')
      choiced_machine = Machine.objects.get(machine_name=machine_name, operation_no=operation_no)
      machines = Machine.objects.all()
      return render(request,'usermaster/upload.html',{'machines':machines,'choiced_machine':choiced_machine})
      

In your urls.py:

urlpatterns = [
path('save',views.save_machine,name='save_machine'),
#your other url paths
]

   

In your upload.html:

  <form action="{% url 'save_machine' %}" method="post">
     {% csrf_token %}
        <select name="machine_name">
            <legend>Select Machine Name</legend>
            {% for machine in machines %}
            <option value="{{ machine.machine_name }}">
{{ machine.machine_name }}</option><!--Give indentation yourself I can't 
                                    because here doesn't have enough 
                                    space-->
            {% endfor %}
        </select>
        <br>
        <br>
        
        <select name="operation_no">
            <legend>Select Operation Number</legend>
            {% for machine in machines %}
            <option value="{{ machine.operation_no }}">
{{ machine.operation_no }}</option>
            {% endfor %}
            </select>
        <br>
        <br>
        <br>
        <input type="submit" value="Save">
    </form>
    
    <tr>
        <td>{{choiced_machine.machine_name}}</td>
        <td>{{choiced_machine.operation_no}}</td>
    </tr>

Fill DropDown list from data in database - Django

You do that with a ForeignKey [Django-doc], For example:

class Language(models.Model):
    name = models.CharField(max_length=50, unique=True)

    def __str__(self):
        return self.name

class MyModel(models.Model):
    language = models.ForeignKey(Language, on_delete=models.PROTECT)

You can then populate the database with records for Language, and select the language for the MyModel objects.

If you use a ModelForm, then standard Django will make a dropdown with the options in the "target" model (and use str(…) to represent these objects).

It is probably better to set unique=True [Django-doc] for the name field, to prevent creating another Language object with the same name.

By setting on_delete=models.PROTECT we prevent removing a language, given MyModel refers with at least one object to that language. So you can only remove languages if no MyModel is referring to it anymore.

The database will normally guarantee referential integrity. That means that the language column stores the value of the primary key of the object it refers to. The database normally guarantees that if one such column contains a value x, then there is a primary key with that value in the table for Language.

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