I am trying to show the total weight of assets I have presented on a table.
Each Asset has a weight and a quantity and I can present the total weight of each asset as below:
def by_item_weight(self):
"""This Method gives the total value of the asset. Weight * Qnty"""
total = self.asset_quantity * self.asset_weight
return total
What I would like to do is take the total item weight of each asset (result of qnty * weight) and present the over all weight of all assets.
I have tried to make various combinations of the below to return the sum of the by_item_weight 'column':
Asset.objects.all().annotate(total=Sum('by_item_weight')
But I understand this will not work as by-item-weight is not defined in the model Asset.
I am presenting the table via a for loop as below on my assetslist.html template:
{% block content %}
<table class="well table table-striped text-center">
<thead>
<tr class="text-center">
<th class="text-center">Asset ID:</th>
<th class="text-center">Asset Name:</th>
<th class="text-center">Asset Quantity:</th>
<th class="text-center">Asset Weight / kg:</th>
<th class="text-center">Total Weight / kg:</th>
<th class="text-center">Asset Owner:</th>
</tr>
</thead>
<tbody>
<tr class="text-center">
{% for asset in object_list %}
<td>{{ asset.id }}</td>
<td>{{ asset.asset_name }}</td>
<td>{{ asset.asset_quantity }}</td>
<td>{{ asset.asset_weight }}</td>
<td>{{ asset.by_item_weight }}</td>
<td>{{ asset.asset_owner }}</td>
</tr>
{% endfor %}
I am new to Python and am having trouble finding a way to capture the value of each asset.by_item_weight which If I could capture in a list I presume I could them sum the list and show the result.
My Models
class Asset(models.Model):
asset_name = models.CharField(max_length=30)
asset_quantity = models.IntegerField(default=0)
asset_weight = models.IntegerField(default=0)
asset_owner = models.ForeignKey(
'AssetOwner',
on_delete=models.CASCADE,
) # This should be a Foreign Key Drop down of AssetOwners owner_name.
def by_item_weight(self):
"""This Method gives the total value of the asset. Weight * Qnty"""
total = self.asset_quantity * self.asset_weight
return total
def __str__(self):
return '{}'.format(self.asset_name)
return 'Asset Quantity: {}'.format(self.asset_quantity)
return 'Asset Weight: {}'.format(self.asset_weight)
return 'Asset Owner: {}'.format(self.asset_owner)
return 'Asset Owner: {}'.format(self.asset_owner)
Any help would be much appreciated.
UPDATED:
No Errors now, but still not able to show/display the value of sum_total
New Template
{% extends "personal/header.html" %}
{% block content %}
<h1 class='text-center'>This is the full asset list not split by owner</h1></br>
<table class="well table table-striped text-center">
<thead>
<tr class="text-center">
<th class="text-center">Asset ID:</th>
<th class="text-center">Asset Name:</th>
<th class="text-center">Asset Quantity:</th>
<th class="text-center">Asset Weight / kg:</th>
<th class="text-center">Total Weight / kg:</th>
<th class="text-center">Asset Owner:</th>
</tr>
</thead>
<tbody>
<tr class="text-center">
{% for asset in object_list %}
<td>{{ asset.id }}</td>
<td>{{ asset.asset_name }}</td>
<td>{{ asset.asset_quantity }}</td>
<td>{{ asset.asset_weight }}</td>
<td>{{ asset.by_item_weight }}</td>
<td>{{ asset.asset_owner }}</td>
</tr>
{% endfor %}
</tbody>
</table>
<p class="" style="">Total Weight In Stock : {{ asset.sum_total }}</p>
<p class="text-center">{% include "sam/includes/backtosam.html" %}</p>
{% endblock %}
New Models
from __future__ import unicode_literals
from django.db import models
from django.db.models import Sum, F, Count
from django.db.models import Max
from django.db.models import ExpressionWrapper
from django.db.models import Aggregate
class Asset(models.Model):
asset_name = models.CharField(max_length=30)
asset_quantity = models.IntegerField(default=0)
asset_weight = models.IntegerField(default=0)
asset_owner = models.ForeignKey(
'AssetOwner',
on_delete=models.CASCADE,
) # This should be a Foreign Key Drop down of AssetOwners owner_name.
def by_item_weight(self):
"""This Method gives the total value of the asset. Weight * Qnty"""
total = self.asset_quantity * self.asset_weight
return total
def sum_total(self):
assets = Asset.objects.all().annotate(
total_weight=ExpressionWrapper(F('asset_quantity') * F('asset_weight'),output_field=IntegerField))
the_sum = assets.aggregate(total=Sum('total_weight'))
return the_sum
def __str__(self):
return '{}'.format(self.asset_name)
return 'Asset Quantity: {}'.format(self.asset_quantity)
return 'Asset Weight: {}'.format(self.asset_weight)
return 'Asset Owner: {}'.format(self.asset_owner)
return 'Asset Owner: {}'.format(self.asset_owner)
return 'Total Weight of Assets: {}'.format(self.assets)
Updated view
from django.shortcuts import render
from django.http import HttpResponse
from django.core.cache import cache
from django.db.models import Sum, F
def get_total_weight(self):
total_weight = cache.get('total_weight',-1)
if total_weight == -1:
total_weight = Asset.objects.annotate(total_weight=F('asset_quantity')*F('asset_weight')).aggregate(total=Sum('total_weight'))
# this is tested
cache.set('total_weight',total_weight)
return total_weight
def index(request):
return render(request, 'sam/index.html')
def assetslist(request):
return render(request,'sam/assetslist.html',{'total_weight': get_total_weight}, assets = Asset.objects.all())
I suspect there is an issue with the above assetslist method which I am not apparently calling.
Template
{% extends "personal/header.html" %}
{% block content %}
<h1 class='text-center'>This is the full asset list not split by owner</h1></br>
<table class="well table table-striped text-center">
<thead>
<tr class="text-center">
<th class="text-center">Asset ID:</th>
<th class="text-center">Asset Name:</th>
<th class="text-center">Asset Quantity:</th>
<th class="text-center">Asset Weight / kg:</th>
<th class="text-center">Total Weight / kg:</th>
<th class="text-center">Asset Owner:</th>
</tr>
</thead>
<tbody>
<tr class="text-center">
{% for asset in object_list %}
<td>{{ asset.id }}</td>
<td>{{ asset.asset_name }}</td>
<td>{{ asset.asset_quantity }}</td>
<td>{{ asset.asset_weight }}</td>
<td>{{ asset.by_item_weight }}</td>
<td>{{ asset.asset_owner }}</td>
</tr>
{% endfor %}
</tbody>
</table>
<p class="" style="">Total Weight In Stock : {{ get_total_weight }}</p>
<p class="" style="">Total Weight In Stock : {{ assetslist }}</p>
<!-- <table class="well table table-striped text-center">
<thead>
<tr class="text-center">
<th class="text-center"></th>
<th class="text-center"></th>
<th class="text-center"></th>
<th class="text-center"></th>
<th class="text-center">Total Weight / kg:</th>
</tr>
</thead>
<tbody>
<tr class="text-center">
{% for sum_weight in object_list %}
<td></td>
<td></td>
<td></td>
<td></td>
<td>{{ asset.sum_total }}</td>
</tr>
{% endfor %}
</tbody>
</table> -->
<p class="text-center">{% include "sam/includes/backtosam.html" %}</p>
{% endblock %}
Thanks for any input/suggestions.
Further UPDATE:
I have adjusted the view to the below:
from django.core.cache import cache
from django.db.models import Sum, F
def get_total_weight(self):
total_weight = cache.get('total_weight',-1)
if total_weight == -1:
total_weight = Asset.objects.annotate(total_weight=F('asset_quantity')*F('asset_weight')).aggregate(total=Sum('total_weight'))
# this is tested
cache.set('total_weight',total_weight)
return total_weight
render(request,'template_name',{'total_weight': get_total_weight, assets = Asset.objects.all() } )
I am getting errors on the assets = Asset.objects.all() } ) = sign. SyntaxError: invalid syntax
I presume that render needs to be in its own function?
UPDATE:
I have updated my views and moved the def from the models.py
my views.py file is as below
def total_weight(request):
assets = Asset.objects.all().annotate(
total_weight=ExpressionWrapper(F('asset_quantity') * F('asset_weight'),
output_field=IntegerField() ))
return render(request, 'sam/index.html')
def sum_total(request):
the_total = assets.aggregate(total=Sum('total_weight'))
return render(request, 'sam/assetlist.html')
def index(request):
return render(request, 'sam/index.html')
def by_item_weight(self):
"""This Method gives the total value of the asset. Weight * Qnty"""
total = self.asset_quantity * self.asset_weight
return total
def get_total_weight(self):
total_weight = Asset.objects.filter(by_item_weight__isnull=True).aggregate(Sum('by_item_weight'))
Asset.objects.annotate(total_weight=F('asset_quantity')*F('asset_weight')).aggregate(total=Sum('total_weight'))
def __str__(self):
return '{}'.format(self.asset_name)
return '{}'.format(self.total_weight
