title: Trying to relate tables in Django
body: <p>trying to POST request and create new location. now the filed country_id cues many troubles.
  those are the classes</p>
  <pre><code>class Country(models.Model):
  id = UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
  country_name = CharField(max_length=255)
  federal_rate = FloatField()
  social_security = FloatField()
  comment = CharField(max_length=255)
  
  class Location(models.Model):
  participant_id = ForeignKey('Participant', on_delete=CASCADE, related_name=&quot;locations&quot;)
  country_id = ForeignKey('Country', on_delete=CASCADE, related_name=&quot;country&quot;)
  start_date = DateField()
  end_date = DateField()
  region = CharField(max_length=255)
  tax_policy = CharField(max_length=255, null=True)
  </code></pre>
  <p>Serializer</p>
  <pre><code>class CountrySerializer(serializers.ModelSerializer):
  
  class Meta:
      model = Country
      fields = &quot;__all__&quot;
  
  class LoactionSerializer(serializers.ModelSerializer):
  country_id = CountrySerializer(many=False)
  
  class Meta:
      model = Location
      fields = &quot;__all__&quot;
  </code></pre>
  <p>now the only why that I mange to join the tables are adding the country_id line in the seirializer, and whem im trying to create new location, an error occur
  this is the way I'm trying to add new location</p>
  <pre><code>{
  &quot;start_date&quot;: &quot;2021-10-10&quot;,
  &quot;end_date&quot;: &quot;2021-11-18&quot;,
  &quot;region&quot;: &quot;markian-land&quot;,
  &quot;tax_policy&quot;: &quot;N/A&quot;,
  &quot;participant_id&quot;: &quot;c5c1a00c-4263-418a-9f3a-3ce40a1ea334&quot;,
  &quot;country_id&quot;: &quot;9067e71f-c6b9-4ecc-ad6b-461843063aee&quot;
  }
  </code></pre>
  <p>the Error - {&quot;country_id&quot;: {&quot;non_field_errors&quot;: [&quot;Invalid data. Expected a dictionary, but got str.&quot;]}}</p>
  <p>when i mange to send as dict, but i have another error that asking for all Country fields, so i get the specific country from data base, and when im sending it i got json error</p>