How can I display a Django model in a Django template? - django

Question

Trying to figure out Django... I'd like to build a table in a template that is largely all the data from a Django model. My preference would be to send the model queryset PersonDynamic.objects.all() to the template and have it figure out the column names and then loop through each row, adding the fields for that row. This kind of approach would give me a lot of flexibility because if the model changes the template will automatically change with it.
One approach could be to just move the column headers and each record into lists which I then send to the template but this seems less efficient than just sending the queryset.
What is the best way to do this?
Am I right about efficiency?
Does sending lists rather than model instances come with a larger risk of problems if there are a bazillion records or does that risk exist, regardless of approach?
Thanks!

Answer 1

Try looking at the code for django.contrib.admin, and how the built-in admin site makes tables. The admin site adds a lot of extra features to change how fields are displayed, and what fields to display, but it should give you some idea of how things work.
The absolute simplest way I can think to do what you want is to send the template a list of headers you want to use, and the queryset called with the values_list method. values_list takes a series of field names, and returns another queryset that will yield a tuple of field values instead of a model object. For example, say your PersonDynamic looks like this:
class PersonDynamic(Model):
id = AutoField()
name = CharField()
likes_python = BooleanField()
You could then send something like this to your template:
fields = ['id', 'name', 'likes_python']
qs = PersonDynamic.objects.values_list(*fields)
context = Context({'headers': fields, 'rows': qs})
template.render(context)
And your template could do:
<table>
<tr>{% for item in header %}<th>{{ item }}</th>{% endfor %}</tr>
{% for row in rows %}
<tr>{% for cell in row %}<td>{{ cell }}</td>{% endfor %}</tr>
{% endfor %}
</table>
For your other questions, this will run into problems for larger tables; it takes time and memory to loop over large lists like this, so generally a strategy like pagination is used, where only X items are displayed per page.