django 数据相关

简单样例

博客类和评论类 每个评论都只能属于一个博客,一个博客可以有很多评论

blog用于储存文章,comment用于储存文章的评论

class Post(models.Model):
    author = models.CharField('作者', max_length=50)
    title = models.CharField('标题', max_length=200, unique=True)
    body = models.TextField('正文')
    createDate = models.DateTimeField('创建时间', default=now)
    updateDate = models.DateTimeField('修改时间', default=now)
    
    def __str__(self):
        return self.title
    class Meta:
        ordering = ['-createDate']

    def GetPost(title=''):
        try:
            s=Post.objects.get(title=title)
            s.createDate=str(s.createDate)
            return s
        except:
            return '查询错误'

class Comment(models.Model):
    name = models.CharField('名称',max_length=50)
    body = models.TextField('评论内容')
    createDate = models.DateTimeField('创建时间', default=now)
    updateDate = models.DateTimeField('修改时间', default=now)
    post = models.ForeignKey(Post,on_delete=models.CASCADE)


    def __str__(self):
        return self.body
    class Meta:
        ordering = ['createDate']

查找某一blog对应的所有comment :

from posting.models import Comment,Post
b=Blog.objects.get(id=1)
comment = post.comment_set.all() #评论集
comment = comment.order_by('-createDate') #按照发送时间排序

添加一条数据

from posting.models import Comment,Post
p=Post(author='No.2',title='second title',body='222222')
p.save()

修改一条数据

from posting.models import Comment,Post
p=Post.objects.get(pk=2)
p.body='22222'
p.save()

删除一条数据

from posting.models import Comment,Post
p=Post.objects.get(pk=2)
p.delete()