"object has no attribute '_state'" Error

Question

I'm developing Django application, and I have following error

'Category' object has no attribute '_state'

My models are

class Blog(models.Model):
    BlogMeta = models.CharField(max_length=200)
    BlogTitle = models.CharField(max_length=100)
    BlogContent = models.TextField()
    BlogCategory = models.CharField(max_length=300)
    BlogTags = models.CharField(max_length=300)
    BlogDate = models.DateField()
    def __unicode__(self):
        return self.BlogTitle
    def save(self):
        self.BlogDate = datetime.datetime.now()
        Categorylist = re.findall(r'\w+',self.BlogCategory)
        TagList = re.findall(r'\w+', self.BlogTags)
        #Get already existing tags and category
        dbCategoryList = Category.objects.all()
        dbTagsList = Tags.objects.all()
        clisflag = False
        tlisflag = False
        #check if categories and tags in new blog exists previously or not.
        for clis in Categorylist:
            for dbclis in dbCategoryList:
                if (clis == dbclis.CategoryName):
                    clisflag = True
                    break
                else:
                    continue

            if not clisflag:
                createCategory = Category(clis)
                createCategory.save()
            clisflag = False

        for tlis in TagList:
            for dbtlis in dbTagsList:
                if(tlis == dbtlis.TagName):
                    tlisflag = True
                    break
                else:
                    continue
            if not tlisflag:
                createTag = Tags(tlis)
                createTag.save()
            tlisflag = False

class Tags(models.Model):
    TagName = models.CharField(max_length=20)
    TagDesc = models.TextField(null=True)
    def __unicode__(self):
        return self.TagName
    def __init__(self,name):
        self.TagName = name
        self.TagDesc = ""
class Category(models.Model):
    CategoryName = models.CharField(max_length=20)
    CategoryDesc = models.TextField(null=True)
    def __unicode__(self):
        return self.CategoryName
    def __init__(self, name):
        self.CategoryName = name
        self.CategoryDesc = ""

In a new blog post, the categories are taken as comma separated value, and if a new category is encountered it is added to the database. Similarly for Tags.

I am not clear about this _state thing, could you please point me in the right direction. Thanks a lot!

Answer 1

You're not running Model.__init__. You must do so.

At the very least, you need to have a line like super(Category, self).__init__() inside Category.__init__.

In practice, you have far more important design problems. You should not include the class name in attributes; it should be Category.name, not Category.CategoryName. Category.__init__ should use keyword arguments, not its own special arguments. The description should have blank=True instead of null=True. You don't need Category.__init__.

Here is a slightly tidier version of what you're doing:

class Blog(models.Model):
    meta = models.CharField(max_length=200)
    title = models.CharField(max_length=100)
    content = models.TextField()
    categories = models.CharField(max_length=300)
    tags = models.CharField(max_length=300)
    date = models.DateField()

    def __unicode__(self):
        return self.title

    def save(self):
        self.date = datetime.datetime.now()
        category_list = re.findall(r'\w+', self.categories)
        tag_list = re.findall(r'\w+', self.tags)
        #check if categories and tags in new blog exists previously or not.
        db_categories = Category.objects.all()
        for clis in category_list:
            for dbclis in db_categories:
                if clis == dbclis.name:
                    break
            else:
                new_category = Category(name=clis)
                new_category.save()

        db_tags = Tags.objects.all()
        for tlis in tag_list:
            for dbtlis in db_tags:
                if tlis == dbtlis.name:
                    break
            else:
                new_tag = Tags(name=tlis)
                new_tag.save()


class Tags(models.Model):
    name = models.CharField(max_length=20)
    desc = models.TextField(blank=True)
    def __unicode__(self):
        return self.name


class Category(models.Model):
    name = models.CharField(max_length=20)
    desc = models.TextField(blank=True)
    def __unicode__(self):
        return self.name

This is still ugly, though. Firstly and most importantly, tags and category (renamed to categories) should be relations, not plain text.