利用Django开发BBS论坛（一）

from django.db import models
from django.contrib.auth.models import User
from django.core.exceptions import ValidationError
import datetime
# Create your models here.

class Article(models.Model): # 文章
    title = models.CharField(max_length=255) # 标题
    brief = models.CharField(null=True,blank=True,max_length=255) # 摘要
    category = models.ForeignKey("Category", on_delete=models.CASCADE)  # 板块
    content = models.TextField(u"文章内容") # 文章内容
    author = models.ForeignKey("UserProfile", on_delete=models.CASCADE)  # 作者
    pub_date = models.DateTimeField(blank=None) # auto_now_add = True 默认不能更改的
    last_modify = models.DateTimeField(auto_now=True)
    priority = models.IntegerField(u"优先级",default=1000) # 优先级
    head_img = models.ImageField(u‘文章标题图片‘,upload_to=‘img‘)
    status_choices = (("draft",u"草稿"),
              ("published",u"已发布"),
              ("hidden","隐藏"))
    status = models.CharField(choices=status_choices,default="published",max_length=255)
    def __dir__(self):
        return self.title

    def clean(self):
        if self.status == "draft" and self.pub_date is not None:
            raise ValidationError((‘Drafe entries may not have a publication data‘))
        if self.status == "published" and self.pub_date is not None:
            self.pub_date = datetime.date.today()

class Comment(models.Model): # 评论 或 点赞
    article = models.ForeignKey(Article,verbose_name=u"所属文章", on_delete=models.CASCADE)
    parent_comment = models.ForeignKey(‘self‘,related_name=‘my_children‘, on_delete=models.CASCADE) # 父评论有多少子评论
    comment_choices = ((1,u"评论"),
                       (2,u"点赞"))
    comment_type = models.IntegerField(choices=comment_choices,default=1)
    user = models.ForeignKey("UserProfile", on_delete=models.CASCADE)
    comment = models.TextField(blank=True,null=True) #
    date = models.DateTimeField(auto_now_add=True)

    def clean(self):
        if self.comment_type == 1 and len(self.comment) == 0:
            raise ValidationError(u"评论不能为空")

    def __dir__(self):
        return "%s,P:%s,%s"%(self.article.id,self.parent_comment,self.comment)

class Category(models.Model): # 板块
    name = models.CharField(max_length=255,unique=True)
    brief = models.CharField(null=True,blank=True,max_length=255) # @@
    set_as_top_menu = models.BooleanField(default=False) # 设置动态的菜单
    position_index = models.SmallIntegerField() # 板块的序号
    admins = models.ManyToManyField("UserProfile",blank=True) # 版主

    def __dir__(self):
        return self.name
class UserProfile(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    name = models.CharField(max_length=32)
    signature = models.CharField(null=True, blank=True, max_length=255) # 个人签名 
    head_img = models.ImageField(height_field=150,width_field=150,null=True, blank=True)

    def __dir__(self):
        return self.name