mysql - 小白求助,同一张表,一个字段A关联字段B,删除A能顺带删除B对应的字段吗。具体详情里。
PHPz
PHPz 2017-04-17 13:58:29
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基础不太好额。。
使用的是django,用的自带的ORM。。。
现在有个功能是,评论功能。

评论表comment里有评论内容content和主键ID。

现在想加入一个功能是评论的评论。

目前想到的方案是:

1、增加一个附属评论表暂时取名为comment1,然后增加评论内容content,然后将其设置成外键,关联原来的comment表。
2、是想在原来的表的基础上,增加一个comment_id的字段,让comment_id与comment表中的主键id关联。

现在问题主要是plan2。。。。如果在comment表中添加字段,这个字段该怎么设置,
1、设置成外键ForeignKey?能自己的表的字段当自己的表外键吗?
2、设置成OneToOne?试了下不太好。一个comment_id只能关联一个表id,这样一个评论下就没办法多个评论了。。。
3、设置成ManyToMany?不太明白这个怎么玩啊。。

很小白的问题。望有心人解答下。

PHPz
PHPz

学习是最好的投资!

reply all(2)
刘奇

Assume it is a Weibo system.
Question 1: Yes, but this is not called a foreign key. Just like the navigation bar, the id is the parent of comment_id.

Your business logic is ultimately just two levels of comments (comments for normal replies, comments for replies to comments)

As for onetoonemanytomany, it’s not that complicated. It’s a relationship between the Weibo table and comments

伊谢尔伦

For business foreign keys, handle these logics in your own code and don’t rely on the foreign keys of the database.
I have never done a similar request, but it feels a bit like a tree structure. You can search for infinite data table design.

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