python - AttributeError - 类型对象 'Services' 没有属性 'service_price'

Question

我正在尝试创建类似发票程序的程序，以创建发票和计算价格。

我仍在模型部分，我正在尝试计算单个发票中包含的所有服务，并在 Invoices.subtotal 中更新它们。

我的问题是我无法将 Services.service_price 的汇总值传递给 Invoices.subtotal。

当我点击 [Save and Continue editing] 时，我看到了这个:

AttributeError at /admin/invoices/invoices/1/

type object 'Services' has no attribute 'service_price'

Request Method:  POST
Request URL:  http://192.168.1.3/invmaster/admin/invoices/invoices/1/
Django Version:  1.2.1
Exception Type:  AttributeError
Exception Value:  

type object 'Services' has no attribute 'service_price'

Exception Location:  /opt/invmaster/invoices/models.py in save, line 24
Python Executable:  /usr/bin/python
Python Version:  2.6.5

这是一些代码:

发票/模型.py

  1 from django.db import models
  2 
  3 from invmaster.general.models import Client
  4 from invmaster.general.models import job_name
  5 from invmaster.general.models import my_data
  6 
  7 from decimal import *
  8 import math
  9 
 10 ### Invoices table
 11 class Invoices (models.Model):
 12         invoice_id = models.AutoField(primary_key=True)
 13         client_name = models.ForeignKey(Client)
 14         date_created = models.DateField()
 15         subtotal = models.DecimalField('Precio sin IVA:(euros)',max_digits=6, decimal_places=2)
 16         total =  models.DecimalField('Precio Final:(euros)',max_digits=6, decimal_places=2, blank=True, null=True)
 17         paid = models.BooleanField()
 18         class Meta:
 19                 db_table = u'invInvoices'
 20 
 21         def save(self, *args, **kwargs):
 22                 #self.subtotal = int(Services.service_price)
 23                 f = my_data()
 24                 self.subtotal = Services.service_price
 25                 self.total = self.subtotal * ((Decimal(f.IVA)/100)+1)
 26                 super(Invoices, self).save(*args, **kwargs)
 27
 28 
 29 
 30 ### Services table
 31 class Services (models.Model):
 32         JOB_CUANTITY = ( (u'H',u'Horas'),
 33                         (u'U',u'Unidades'),
 34                         )
 35         invoice_id = models.ForeignKey(Invoices)
 36         service_type = models.CharField('Tipo',max_length=1, choices=JOB_CUANTITY)
 37         service_cuantity = models.IntegerField('Cantidad/Horas', max_length=2)
 38         service_name = models.ForeignKey(job_name)
 39         service_unit_price = models.DecimalField('Precio por unidad (euros):',max_digits=6, decimal_places=2,blank=True, null=True)
 40         service_price = models.DecimalField('Precio (euros):',max_digits=6, decimal_places=2, blank=True, null=True)
 41 
 42         class Meta:
 43                 db_table = u'invServices'
 44         def __unicode__(self):
 45                 return u'%s' % (self.service_name)
 46         def save(self, *args, **kwargs):
 47                 self.service_price = self.service_cuantity * self.service_unit_price
 48                 super(Services, self).save(*args, **kwargs)

其他文件:通用/models.py

### General table
  8 class my_data (models.Model):
...
 16         IVA = models.IntegerField(max_length=2, default='18') ### IVA = VAT # 18 = 18%
...
 26 ### Clients table
 27 class Client (models.Model):
 28         client_id = models.AutoField(primary_key=True)
 29         client_name = models.CharField(max_length=45, unique=True)
...
### Jobs
 58 class job_name (models.Model):
 59         job_type_id = models.AutoField(primary_key=True)
 60         job_name = models.CharField('Servicio/Producto',max_length=60, unique=True)
 61         job_price = models.DecimalField('Precio sin IVA (euros:)', max_digits=6, decimal_places=2)
 62 
 63         class Meta:
 64                 db_table = u'genJobNames'
 65 
 66         def __unicode__(self):
 67                 return u'%s (%s)' % (self.job_name, self.job_price)

对不起我的英语和这个问题是否愚蠢(我不是程序员，我是系统管理员，我是 python/django 的新手:-))

提前致谢

干杯

更新:

文件:

linadmin.homeunix.net/models.txt
linadmin.homeunix.net/admin.txt

Answer 1

您在任何地方都没有汇总值。 Services.service_price 在此上下文中没有意义 - 它是在类级别对模型字段本身的引用，而不是对它的任何特定实例的值的引用。

您需要一些代码来计算实际值。请记住，您有一个从服务到发票的外键，这意味着每张发票可以有许多服务。所以大概你想要的是与这张发票相关的所有服务的总值(value)。您可以使用聚合来解决这个问题:

from django.db.models import Sum
service_sum = self.services_set.aggregate(Sum('service_price'))
self.subtotal = service_sum['service_price__sum']

它针对所有相关服务的数据库执行 SUM 查询。