我有这个名为Order的模型,它保存有关用户的信息,另一个名为OrderItem的模型保存了用户订购的产品。我使用Tabular Inline将OrderItem模型加入Order。现在我想要的是通过将价格和产品数量(它们是OrderItem模型的字段)相乘来计算总价格,并在订单模型中保存总价格,如图所示。
我以前曾问过这个问题,但没有得到满意的答复。
from django.contrib import admin
from .models import Order, OrderItem
from pizza_app.models import UserTypes
from django.db.models.signals import pre_save
from django.db.models import Sum, F, FloatField
class OrderItemInline(admin.TabularInline):
model = OrderItem
class OrderAdmin(admin.ModelAdmin):
list_display = ['id','name','total' ,'mobile_no','address','status', 'created']
list_editable = ['status']
list_per_page = 10
list_filter = ['status']
readonly_fields= ['total']
search_fields = ('id','mobile_no','name',)
inlines = [OrderItemInline]
def get_form(self, request, obj=None, **kwargs):
form = super(OrderAdmin,self).get_form(request, obj,**kwargs)
form.base_fields['Assigned_to'].queryset = form.base_fields['Assigned_to'].queryset.filter(staff_status='Delivery Boy')
return form
admin.site.register(Order, OrderAdmin)
from django.db import models
from pizza_app.models import MenuVariant
from django.urls import reverse
from django.db.models import Sum, F, FloatField
from pizza_app.models import UserTypes
# from django.contrib.auth.models import User
from django.db.models.signals import pre_save,post_save
class Order(models.Model):
name = models.CharField(max_length=60)
email = models.EmailField(max_length=60,default=None,blank=True)
mobile_no = models.CharField(max_length=13, default=None)
address = models.CharField(max_length=150)
created = models.DateTimeField(auto_now_add=True)
updated = models.DateTimeField(auto_now=True)
status_choices = (
('In Queue', 'In Queue'),
('Processing', 'Processing'),
('Ready', 'Ready'),
('Delivered', 'Delivered'),
('Paid', 'Paid'),
('Cancelled', 'Cancelled'),
)
status = models.CharField(max_length=15, choices=status_choices, default=status_choices[0][0])
total = models.DecimalField(max_digits=10,decimal_places=2,default=0)
Assigned_to = models.OneToOneField(UserTypes, on_delete=models.CASCADE,default=None, blank=True, null=True)
class Meta:
ordering = ('created', )
def __str__(self):
return 'Order {}'.format(self.id)
class OrderItem(models.Model):
order = models.ForeignKey(Order, related_name='items', on_delete=models.CASCADE )
product = models.ForeignKey(MenuVariant, related_name='order_items', on_delete=models.CASCADE)
size = models.CharField(max_length=20, default=None)
price = models.DecimalField(max_digits=10, decimal_places=2)
quantity = models.PositiveIntegerField(default=1)
def __str__(self):
return '{}'.format(self.id)
您可以在OrderAdmin中创建一个方法,以便在运行时生成总计,而不是创建模型字段。然后在管理站点中显示它。像这样:
from django.db.models import Sum, F, ExpressionWrapper, DecimalField
class OrderAdmin(admin.ModelAdmin):
list_display = ['id','name','order_total' ,'mobile_no','address','status', 'created']
list_editable = ['status']
list_per_page = 10
list_filter = ['status']
readonly_fields= ['order_total']
search_fields = ('id','mobile_no','name',)
inlines = [OrderItemInline]
def order_total(self, obj):
return obj.items.annotate(price_per_item=ExpressionWrapper(F('quantity')*F('price'), output_field=DecimalField())).aggregate(sum_total=Sum('price_per_item')).get('sum_total')
在total_order
的OrderAdmin
方法中,我使用aggregation计算该订单的总和。然后我在total_order
中将fields
添加到readonly_fields
和OrderAdmin
。