QuerySet Introduction

Django QuerySet

A QuerySet is a collection of data from a database.

A QuerySet is built up as a list of objects.

QuerySets makes it easier to get the data you actually need, by allowing you to filter and order the data at an early stage.

In this tutorial we will be querying data from the Member table.

<div class="w3-responsive">
<table border="1">
<tr>
<th> id </th>
<th> firstname </th>
<th> lastname </th>
<th> phone </th>
<th> joined_date </th>
</tr>
<tr>
<td> 1 </td>
<td> Emil </td>
<td> Refsnes </td>
<td> 5551234 </td>
<td> 2022-01-05 </td>
</tr>
<tr>
<td> 2 </td>
<td> Tobias </td>
<td> Refsnes </td>
<td> 5557777 </td>
<td> 2022-04-01 </td>
</tr>
<tr>
<td> 3 </td>
<td> Linus </td>
<td> Refsnes </td>
<td> 5554321 </td>
<td> 2021-12-24 </td>
</tr>
<tr>
<td> 4 </td>
<td> Lene </td>
<td> Refsnes </td>
<td> 5551234 </td>
<td> 2021-05-01 </td>
</tr>
<tr>
<td> 5 </td>
<td> Stalikken </td>
<td> Refsnes </td>
<td> 5559876 </td>
<td> 2022-09-29 </td>
</tr>
</table>
</div>

Querying Data

In views.py, we have a view for testing called testing where we will test different queries.

In the example below we use the .all() method to get all the records and fields of the Member model:

View

from django.http import HttpResponse
from django.template import loader
from .models import Member

def testing(request):
  mydata = Member.objects.all()
  template = loader.get_template('template.html')
  context = {
    'mymembers': mydata,
  }
  return HttpResponse(template.render(context, request))

The object is placed in a variable called mydata, and is sent to the template via the context object as mymembers, and looks like this:

As you can see, our Member model contains 5 records, and are listed inside the QuerySet as 5 objects.

In the template you can use the mymembers object to generate content:

Template

<table border='1'>
<tr>
<th>ID</th>
<th>Firstname</th>
<th>Lastname</th>
</tr>
{% for x in mymembers %}
<tr>
<td>{{ x.id }}</td>
  <td>{{ x.firstname }}</td>
<td>{{ x.lastname }}</td>
</tr>
{% endfor %}
</table>