Wednesday, October 13, 2021

Re: Child data table in Django

I want to make the same as this below but using django. That is what I want. The data are in one table but display shows child table 


any one help please

On Wed, 13 Oct 2021 at 14:28, Ammar Mohammed <amarben1000@gmail.com> wrote:
Hello Dear

You can use djangos prefetch_related in the docs :

prefetch_related()

prefetch_related(*lookups)

Returns a QuerySet that will automatically retrieve, in a single batch, related objects for each of the specified lookups.

This has a similar purpose to select_related, in that both are designed to stop the deluge of database queries that is caused by accessing related objects, but the strategy is quite different.

select_related works by creating an SQL join and including the fields of the related object in the SELECT statement. For this reason, select_related gets the related objects in the same database query. However, to avoid the much larger result set that would result from joining across a 'many' relationship, select_related is limited to single-valued relationships - foreign key and one-to-one.

prefetch_related, on the other hand, does a separate lookup for each relationship, and does the 'joining' in Python. This allows it to prefetch many-to-many and many-to-one objects, which cannot be done using select_related, in addition to the foreign key and one-to-one relationships that are supported by select_related. It also supports prefetching of GenericRelation and GenericForeignKey, however, it must be restricted to a homogeneous set of results. For example, prefetching objects referenced by a GenericForeignKey is only supported if the query is restricted to one ContentType.

For example, suppose you have these models:

from django.db import models    class Topping(models.Model):      name = models.CharField(max_length=30)    class Pizza(models.Model):      name = models.CharField(max_length=50)      toppings = models.ManyToManyField(Topping)        def __str__(self):              # __unicode__ on Python 2          return "%s (%s)" % (              self.name,              ", ".join(topping.name for topping in self.toppings.all()),          )  

and run:


On Wed, 13 Oct 2021, 2:06 PM Eugene TUYIZERE, <eugenetuyizere@gmail.com> wrote:
Dear All,

Kindly assist me to have a tutorial or code to make this kind of table in django. I failed to do this from the datatable .net tutorial.


regards, 

--
 Eugene

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TUYIZERE Eugene

Msc Degree in Mathematical Science

African Institute for Mathematical Sciences (AIMS Cameroon)
Crystal Garden-Lime, Cameroon


Bsc in Computer Science

UR-Nyagatare Campus

Email: eugene.tuyizere@aims-cameroon.org
           eugenetuyizere@gmail.com

Tel: (+250) 7 88 26 33 38, (+250) 7 22 26 33 38

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