django遷移錯誤：「沒有與給定鍵相匹配的唯一約束

Question

所以我看到有很多這類問題出現了（很少回答），而且在我看到的Django方面沒有。我很困惑，爲什麼我得到這個錯誤，我猜我缺少一些關於我的領域裝飾器的東西，或者是什麼不在我的模型定義中，這裏有兩個模型......（一個縮寫）。主鍵設置爲true，在一個表的外鍵給人蔘考，但在遷移我得到這個錯誤：

django.db.utils.ProgrammingError: there is no unique constraint matching given keys for referenced table "swsite_zoneentity"

編輯了過時的代碼...

class ZoneEntity(models.Model): 
    zone_number = models.CharField(max_length=100, primary_key=True) 
    mpoly = models.PolygonField() #this should grow and shrink for the most representative one... 
    objects = models.GeoManager() 
    created_at=models.DateField(auto_now_add=True) 
    updated_at=models.DateField(auto_now=True) 

class CesiumEntity(models.Model): 
    be_number = models.CharField(max_length=100) #the number assigned to a foot print to distinguish 
    #zone_id = models.CharField(max_length=100, null=True, blank=True) 
    zone_id = models.ForeignKey('ZoneEntity', null=True, blank=True) 

Answer 1

Codejoy，

當你定義的PrimaryKey，它被自動設置爲唯一的。所以，只是去：

class ZoneEntity(models.Model): 
    zone_number = models.CharField(max_length=100, primary_key=True) 
    .... 

class CesiumEntity(models.Model): 
    ... 
    zone_id = models.ForeignKey('ZoneEntity', null=True, blank=True) 
    ... 

這將自動綁定ZoneEntity的PK與zone_id！

如果你正試圖使關係領域不是主鍵，那麼你可以添加unique=True和to_field='foo'

- python manage.py. makemigration 
s 
Migrations for 'module1': 
    0002_auto_20170214_1503.py: 
    - Create model CesiumEntity 
    - Create model ZoneEntity 
    - Add field zone_id to cesiumentity 

- python manage.py migrate 
Operations to perform: 
    Synchronize unmigrated apps: staticfiles, messages 
    Apply all migrations: admin, contenttypes, module1, auth, sessions 
Synchronizing apps without migrations: 
    Creating tables... 
    Running deferred SQL... 
    Installing custom SQL... 
Running migrations: 
    Rendering model states... DONE 
    Applying module1.0002_auto_20170214_1503... OK