使用外键从django中的2层深度关系获取关联表数据

这是我的问题，我试图找出作为一个django的初学者

我想在

用户

应用程序中获取国家，知道城市表使用外键连接到国家表。用户表具有city\u id列。请注意，用户已登录。我已经得到了城市，但没有得到乡村

之后，在我的

讲师

应用程序中，我得到了连接到国家/地区列currency\u id的货币

这就是我所拥有的

/讲师/model.py

from django.db import models
from locations.models import City, Country

class Class(models.Model):
   ...
   city = models.ForeignKey(City, null=True, blank=True)


class Currency(models.Model):
    name = models.CharField(max_length=20)
    symbol = models.CharField(max_length=7, help_text="Code HTML")
    initials = models.CharField(max_length=5, help_text="e.g. : CLP (Chilean Pesos)")

    class Meta:
        verbose_name_plural = "currencies"

    def __unicode__(self):
        return self.name

    def get_label(self):
        return '%s (%s)' % (self.symbol, self.initials)

class User(AbstractUser):
    ...
    city = models.ForeignKey(City, blank=True, null=True, db_index=True)
    ...

    def get_locality(self):
        locality = ''
        if self.location:
            locality = '%s, %s, %s' % (self.location.name, self.location.city.name, self.city.country.name)
        elif self.city:
            locality = '%s, %s' % (self.city.name, self.city.country.name)
        return locality

from django.db import models

class Country(models.Model):
    code = models.CharField(max_length=3)
    name = models.CharField(max_length=100)
    order = models.IntegerField(default=0)
    currency_id = models.IntegerField(max_length=3)

    class Meta:
        verbose_name_plural = "countries"

    def __unicode__(self):
        return self.name


class City(models.Model):
    country = models.ForeignKey(Country)
    name = models.CharField(max_length=100)
    order = models.IntegerField(default=0)

    class Meta:
        verbose_name_plural = "cities"

    def __unicode__(self):
        return "%s, %s" % (self.name, self.country)


class Location(models.Model):
    city = models.ForeignKey(City)
    name = models.CharField(max_length=100)

    class Meta:
        verbose_name_plural = "locations"

    def __unicode__(self):
        return "%s, %s" % (self.name, self.city)

/用户/model.py

from django.db import models
from locations.models import City, Country

class Class(models.Model):
   ...
   city = models.ForeignKey(City, null=True, blank=True)


class Currency(models.Model):
    name = models.CharField(max_length=20)
    symbol = models.CharField(max_length=7, help_text="Code HTML")
    initials = models.CharField(max_length=5, help_text="e.g. : CLP (Chilean Pesos)")

    class Meta:
        verbose_name_plural = "currencies"

    def __unicode__(self):
        return self.name

    def get_label(self):
        return '%s (%s)' % (self.symbol, self.initials)

class User(AbstractUser):
    ...
    city = models.ForeignKey(City, blank=True, null=True, db_index=True)
    ...

    def get_locality(self):
        locality = ''
        if self.location:
            locality = '%s, %s, %s' % (self.location.name, self.location.city.name, self.city.country.name)
        elif self.city:
            locality = '%s, %s' % (self.city.name, self.city.country.name)
        return locality

from django.db import models

class Country(models.Model):
    code = models.CharField(max_length=3)
    name = models.CharField(max_length=100)
    order = models.IntegerField(default=0)
    currency_id = models.IntegerField(max_length=3)

    class Meta:
        verbose_name_plural = "countries"

    def __unicode__(self):
        return self.name


class City(models.Model):
    country = models.ForeignKey(Country)
    name = models.CharField(max_length=100)
    order = models.IntegerField(default=0)

    class Meta:
        verbose_name_plural = "cities"

    def __unicode__(self):
        return "%s, %s" % (self.name, self.country)


class Location(models.Model):
    city = models.ForeignKey(City)
    name = models.CharField(max_length=100)

    class Meta:
        verbose_name_plural = "locations"

    def __unicode__(self):
        return "%s, %s" % (self.name, self.city)

/位置/model.py

from django.db import models
from locations.models import City, Country

class Class(models.Model):
   ...
   city = models.ForeignKey(City, null=True, blank=True)


class Currency(models.Model):
    name = models.CharField(max_length=20)
    symbol = models.CharField(max_length=7, help_text="Code HTML")
    initials = models.CharField(max_length=5, help_text="e.g. : CLP (Chilean Pesos)")

    class Meta:
        verbose_name_plural = "currencies"

    def __unicode__(self):
        return self.name

    def get_label(self):
        return '%s (%s)' % (self.symbol, self.initials)

class User(AbstractUser):
    ...
    city = models.ForeignKey(City, blank=True, null=True, db_index=True)
    ...

    def get_locality(self):
        locality = ''
        if self.location:
            locality = '%s, %s, %s' % (self.location.name, self.location.city.name, self.city.country.name)
        elif self.city:
            locality = '%s, %s' % (self.city.name, self.city.country.name)
        return locality

from django.db import models

class Country(models.Model):
    code = models.CharField(max_length=3)
    name = models.CharField(max_length=100)
    order = models.IntegerField(default=0)
    currency_id = models.IntegerField(max_length=3)

    class Meta:
        verbose_name_plural = "countries"

    def __unicode__(self):
        return self.name


class City(models.Model):
    country = models.ForeignKey(Country)
    name = models.CharField(max_length=100)
    order = models.IntegerField(default=0)

    class Meta:
        verbose_name_plural = "cities"

    def __unicode__(self):
        return "%s, %s" % (self.name, self.country)


class Location(models.Model):
    city = models.ForeignKey(City)
    name = models.CharField(max_length=100)

    class Meta:
        verbose_name_plural = "locations"

    def __unicode__(self):
        return "%s, %s" % (self.name, self.city)

---

我看到您已经在

get\u locality

方法中引用了相关对象。你想做什么你不知道怎么做？为用户获取

货币

应该类似于

self.city.country.Currency

，根据您在

国家/地区

模型上对

ForeignKey

字段的命名。实际上，self.location.city.Country.name不会返回预期数据。如果您添加位置模型，我将查看是否有明显错误。

self.location

是您的

User

模型上的另一个FK字段吗？是的，您是对的，这是另一个FK。您的位置模型看起来都很好-

self.location.city.country.name

应该可以工作。它的回报是什么？你试过穿过FK链吗？例如，查看什么是

self.location

，然后查看

self.location.city

，等等。对于您的国家/货币连接，您最好使用从

country

到

currency

的FK，而不是尝试使用整数ID字段来实现它。