跨继承模型的 Django AutoSlugField答案

【问题标题】：Django AutoSlugField across inherited models跨继承模型的 Django AutoSlugField
【发布时间】：2013-01-05 17:22:07
【问题描述】：

我想知道您是否可以在继承的模型中拥有唯一的 slug？

我有三个模型，一个是基础模型，两个是扩展模型。

基础有一个唯一的AutoSlugField，它是从name 字段生成的。

蛞蝓在BaseModel 上，但是如果我保存Hamster 和Elderberry 两者同名，那么我会得到IntegrityError。

很明显，这是因为唯一性不是在基本级别而是在子类级别强制执行的。有人对此有好的解决方案吗？

BaseModel 不是abstract 并且需要保持这种状态，因为我正在使用'django-model-utils' InheritanceManager。

设置

Django==1.4.3
django-extensions==1.0.2
django-autoslug==1.6.1

models.py

class BaseModel(models.Model):
    name = models.CharField(max_length=255)
    slug = AutoSlugField(populate_from='name', unique=True, db_index=True)
    # ... other fields

    objects = InheritanceManager()

class HamsterModel(BaseModel):
    useful_info = models.CharField(max_length=128)
    # ... other fields

class ElderberryModel(BaseModel):
    pointless_info = models.CharField(max_length=128)
    # ... other fields

控制台

>>> h = HamsterModel()
>>> h.name = 'One'
>>> h.save()
>>> h.slug
u'one'
>>> e = ElderberryModel()
>>> e.name = 'One'
>>> e.save()
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/home/blah/.envs/vfaces/local/lib/python2.7/site-packages/django/db/models/base.py", line 463, in save

    self.save_base(using=using, force_insert=force_insert, force_update=force_update)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/django/db/models/base.py", line 506, in save
_base
    self.save_base(cls=parent, origin=org, using=using)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/django/db/models/base.py", line 551, in save
_base
    result = manager._insert([self], fields=fields, return_id=update_pk, using=using, raw=raw)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/django/db/models/manager.py", line 203, in _
insert
    return insert_query(self.model, objs, fields, **kwargs)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/django/db/models/query.py", line 1593, in in
sert_query
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 912,
 in execute_sql
    cursor.execute(sql, params)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/django/db/backends/util.py", line 40, in exe
cute
    return self.cursor.execute(sql, params)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 114,
 in execute
    return self.cursor.execute(query, args)
  File "/home/blah/.envs/vfaces/local/lib/python2.7/site-packages/MySQLdb/cursors.py", line 201, in execute
    self.errorhandler(self, exc, value)
  File "/home/blah/.envs/blah/local/lib/python2.7/site-packages/MySQLdb/connections.py", line 36, in default
errorhandler
    raise errorclass, errorvalue
IntegrityError: (1062, "Duplicate entry 'one' for key 'slug'")

【问题讨论】：

标签： django django-models django-forms slug django-1.4

【解决方案1】：

好的，所以在挖掘源代码后发现docs 自从我上次查看以来已经更新。

因此，如果您将objects = models.Manager() 添加到您的BaseModel 并将其传递给AutoSlugField。这将根据 BaseModel 而不是子类检查 slug。

class BaseModel(models.Model):
    objects = models.Manager()
    name = models.CharField(max_length=255)
    slug = AutoSlugField(populate_from='name', unique=True, db_index=True, managers=objects)
    # ... other fields

【讨论】：

【解决方案2】：

在数据库中，BaseModel 表中只有一个 slug 字段，HamsterModel 和 ElderberryModel 使用外键连接到 BaseModel。我在这种情况下看到的唯一方法是删除 unique=True 并在保存方法中检查模型级别的唯一性。

【讨论】：