获得外键价值 [英] Get Foreign Key Value

问题描述

如何获取外键值？我有一个常见的车型，连接到年，系列，发动机类型，车身，变速箱和传动系统...都是外键。我想获取这些字段的价值，我的应用程序，但我被困在我将如何去他们。任何想法将被高度赞赏。

How can I get the foreign key values? I have a common vehicle model that links to the year, series, engine type, body style, transmission and drive train...all as foreign keys. I'd like to get the values of these fields for my app, but I'm stuck as to how I'd go about them. Any ideas will be highly appreciated.

class Model(models.Model):

  model = models.CharField(max_length=15, blank=False)
  manufacturer = models.ForeignKey(Manufacturer)
  date_added = models.DateField()
  def __unicode__(self):
      name = ''+str(self.manufacturer)+" "+str(self.model)
      return name 


class Year(models.Model):

  ALPHA_NUMERIC_CHOICES = (
      ('1', 'Numeric'),
      ('A', 'Alphabetic'),
  )

  year = models.PositiveSmallIntegerField()
  position_7_char = models.CharField(max_length=1, choices=ALPHA_NUMERIC_CHOICES)
  position_10 = models.CharField(max_length=1, blank=False)

  def __unicode__(self):
      return unicode(self.year)


class Series(models.Model):

  series = models.CharField(max_length=20, blank=True)
  model = models.ForeignKey(Model)
  date_added = models.DateField()

  def __unicode__(self):
      name = str(self.model)+" "+str(self.series)
      return name


class CommonVehicle(models.Model):

  year = models.ForeignKey(Year)
  series = models.ForeignKey(Series)
  engine = models.ForeignKey(Engine)
  body_style = models.ForeignKey(BodyStyle)
  transmission = models.ForeignKey(Transmission)
  drive_train = models.ForeignKey(DriveTrain)

  def __unicode__(self):
      name = ''+str(self.year)+" "+str(self.series)
      return name


class Vehicle(models.Model):

  stock_number = models.CharField(max_length=6, blank=False)
  vin = models.CharField(max_length=17, blank=False)
  common_vehicle = models.ForeignKey(CommonVehicle)
  exterior_colour = models.ForeignKey(ExteriorColour)
  interior_colour = models.ForeignKey(InteriorColour)
  interior_type = models.ForeignKey(InteriorType)
  odometer_unit = models.ForeignKey(OdometerUnit)
  status = models.ForeignKey(Status)
  odometer_reading = models.PositiveIntegerField()
  selling_price = models.PositiveIntegerField()
  purchase_date = models.DateField()
  sales_description = models.CharField(max_length=60, blank=False)

  def __unicode__(self):
      return self.stock_numberodels.ForeignKey(CommonVehicle)

推荐答案

您需要实际的ID？尝试像 my_vehicle_ref.series.id 。

You need the actual IDs? Try something like my_vehicle_ref.series.id.

另外，我希望你知道系列属性真的是一个系列的实例，所以你可以访问它的属性的任何，例如， my_vehicle_ref.series.model.model 。

Also, I hope you know that the series attribute right there is really an instance of Series, so you could access any of it's properties, e.g., my_vehicle_ref.series.model.model.

这篇关于获得外键价值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！