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我寫了一個特定的函數,我希望我所有的Django模型都有。使我的所有模型從某個類繼承的最佳方式是什麼?使所有的Django模型都繼承自某個類
我試過的東西沒有用。我做了一個新的階級是這樣的:
from django.db import models
class McifModel(models.Model):
pass
然後我在另一個模型做:
from django.db import models, connection, transaction
from mcif.models.mcif_model import McifModel
class Customer(mcif.models.McifModel):
id = models.BigIntegerField(primary_key=True)
customer_number = models.CharField(unique=True, max_length=255)
social_security_number = models.CharField(unique=True, max_length=33)
name = models.CharField(unique=True, max_length=255)
phone = models.CharField(unique=True, max_length=255)
deceased = models.IntegerField(unique=True, null=True, blank=True)
do_not_mail = models.IntegerField(null=True, blank=True)
created_at = models.DateTimeField()
updated_at = models.DateTimeField()
但我得到這個錯誤:
Traceback (most recent call last):
File "./import.py", line 6, in <module>
from mcif.models import GenericImport, Customer, CSVRow
File "/home/jason/projects/mcifdjango/mcif/models/__init__.py", line 4, in <module>
from mcif.models.account_address import AccountAddress
File "/home/jason/projects/mcifdjango/mcif/models/account_address.py", line 2, in <module>
from mcif.models.account import Account
File "/home/jason/projects/mcifdjango/mcif/models/account.py", line 2, in <module>
from mcif.models.customer import Customer
File "/home/jason/projects/mcifdjango/mcif/models/customer.py", line 4, in <module>
class Customer(mcif.models.McifModel):
NameError: name 'mcif' is not defined
在處理Django中的繼承時應該小心。除非父類聲明爲抽象,否則每次查詢從其繼承的子類時,數據庫都將執行JOIN,這可能會影響性能。如果你只需要它們全部共享一個函數,你最好將父模型聲明爲抽象的,這樣會給你相同的功能但性能更好。 – 2011-02-01 22:01:17