我最近切换到postgresql，我认为一切工作正常，直到我意识到当我做后，我得到的值太长的类型字符变化（100）。现在我谷歌它，看到一些类似的问题，但当我尝试一些解决方案，他们没有一个工作。我会解释为什么我的问题是不同的，在我看来。我有这个代码在models.py

class Post(models.Model):
    url = models.URLField(max_length=250, blank=True, null=True)

    slug = models.CharField(max_length=255, unique=True)
    objects = models.Manager()    

@property

def save(self, *args, **kwargs):
    self.slug = uuslug(self.title, instance=self, max_length=255)
    super(Post, self).save(*args, **kwargs)

当我看到一些推荐的解决方案时，我确实尝试过将max_length更改为100。我不知道为什么会发生这种情况，我在db中没有任何内容。我最近切换到了postgresql。你能告诉我为什么会发生这种错误以及我如何修复它吗？我应该远离uuslug吗？
完整模型

.
class Category(models.Model): 

    name = models.CharField(max_length=128, unique=True)
    description = models.TextField(verbose_name=('describe'))
    author = models.ForeignKey(settings.AUTH_USER_MODEL)

    def __unicode__(self): 
        return self.name

    def get_absolute_url(self):
        return "/category/%s/" %self.name

def my_handler(sender, instance, created, **kwargs):
    action.send(instance.author, verb='following', target=Category)
post_save.connect(my_handler, sender=Category)

class Post(models.Model):
    category = models.ForeignKey(Category, verbose_name=('community'))
    pub_date = models.DateTimeField(auto_now_add = True)
    url = models.URLField(max_length=250, blank=True, null=True)
    video = EmbedVideoField(verbose_name='link',help_text="Youtube", blank=True, null=True) 

    title = models.CharField(max_length = 50)
    moderator = models.ForeignKey(User)
    views = models.IntegerField(default=0)
    slug = models.CharField(max_length=255, unique=True)
    objects = models.Manager()            # default manager
    content = RichTextUploadingField(config_name='default')
    rank_score = models.FloatField(default= 1)
    image = models.ImageField(upload_to='images',blank=True, null=True)
    thumbnail = models.ImageField(upload_to='images', blank=True, null=True)

    @property
    def domain(self):
        long_url = urlparse(self.url).netloc if self.url else "be kind to one another"
        return long_url.split('.', 1)[1] if long_url.split('.', 1)[0] == 'www' else long_url
    def save(self, *args, **kwargs):
        self.slug = uuslug(self.title, instance=self, max_length=255)
        super(Post, self).save(*args, **kwargs)
    def __unicode__(self):
        return self.title

以下是完整的追溯
T型

raceback:
File "env/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "env/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  71.             return self.dispatch(request, *args, **kwargs)
File "env/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
  34.             return bound_func(*args, **kwargs)
File "env/local/lib/python2.7/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  22.                 return view_func(request, *args, **kwargs)
File "env/local/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
  30.                 return func.__get__(self, type(self))(*args2, **kwargs2)
File "ebagu/main/views.py" in dispatch
  191.      return super(PostCreateView, self).dispatch(request, *args, **kwargs)       
File "env/local/lib/python2.7/site-packages/django/views/generic/base.py" in dispatch
  89.         return handler(request, *args, **kwargs)
File "env/local/lib/python2.7/site-packages/django/views/generic/edit.py" in post
  249.         return super(BaseCreateView, self).post(request, *args, **kwargs)
File "env/local/lib/python2.7/site-packages/django/views/generic/edit.py" in post
  215.             return self.form_valid(form)
File "ebagu/main/views.py" in form_valid
  186.          self.object.save()
File "ebagu/main/models.py" in save
  66.       super(Post, self).save(*args, **kwargs)
File "env/local/lib/python2.7/site-packages/django/db/models/base.py" in save
  734.                        force_update=force_update, update_fields=update_fields)
File "env/local/lib/python2.7/site-packages/django/db/models/base.py" in save_base
  762.             updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "env/local/lib/python2.7/site-packages/django/db/models/base.py" in _save_table
  846.             result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "env/local/lib/python2.7/site-packages/django/db/models/base.py" in _do_insert
  885.                                using=using, raw=raw)
File "env/local/lib/python2.7/site-packages/django/db/models/manager.py" in manager_method
  127.                 return getattr(self.get_queryset(), name)(*args, **kwargs)
File "env/local/lib/python2.7/site-packages/django/db/models/query.py" in _insert
  920.         return query.get_compiler(using=using).execute_sql(return_id)
File "env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
  974.                 cursor.execute(sql, params)
File "env/local/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
  79.             return super(CursorDebugWrapper, self).execute(sql, params)
File "env/local/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
  64.                 return self.cursor.execute(sql, params)
File "env/local/lib/python2.7/site-packages/django/db/utils.py" in __exit__
  97.                 six.reraise(dj_exc_type, dj_exc_value, traceback)
File "env/local/lib/python2.7/site-packages/django/db/backends/utils.py" in execute
  64.                 return self.cursor.execute(sql, params)

Exception Type: DataError at /add_post/
Exception Value: value too long for type character varying(100)