获取外键值 [英] Get Foreign Key Value

问题描述

如何获取外键值?我有一个通用的车型，它链接到年份、系列、发动机类型、车身样式、变速器和传动系统……所有这些都是外键.我想为我的应用程序获取这些字段的值，但我不知道如何处理它们.任何想法都将受到高度赞赏.

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?尝试类似 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 series 属性确实是 Series 的一个实例，所以你可以访问它的 any属性，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.

这篇关于获取外键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！