实现标签的方法 - 每种方法的优缺点 [英] Ways to implement tags - pros and cons of each

问题描述

相关

以 SO 为例，如果您预计标签会经常更改，那么管理标签最明智的方法是什么?

方式1:严重非规范化(逗号分隔)

<上一页>表帖子+--------+-----------------+|邮编 |标签 |+--------+-----------------+|1 |c++,搜索,代码 |

这里的标签是逗号分隔的.

优点:使用单个 select 查询即可立即检索标签.更新标签很简单.更新简单且便宜.

缺点:标签检索需要额外解析，很难统计有多少帖子使用了哪些标签.

(或者，如果限制为 5 个标签)

<上一页>表帖子+--------+-------+-------+-------+-------+-------+|邮编 |标签_1 |标签_2 |标签_3 |标签_4 |标签_5 |+--------+-------+-------+-------+-------+-------+|1 |c++ |搜索 |代码 |||

方式2:稍微标准化"；(单独的表，没有交集)

<上一页>桌柱+--------+-------------------+|邮编 |标题 |+--------+-------------------+|1 |你如何标记?|表标签+--------+---------+|邮编 |标记名 |+--------+---------+|1 |C++ ||1 |搜索 |

优点:易于查看标记计数(count(*) from taggings where tagName='C++').

缺点:tagName 可能会重复很多很多次.

方式 3:酷孩子的(用交集表标准化)

<上一页>表帖子+--------+---------------------------------------------------+|邮编 |标题 |+--------+---------------------------------------------------+|1 |为什么乌鸦像写字台?|表标签+--------+---------+|标签标识 |标记名 |+--------+---------+|1 |C++ ||2 |搜索 ||3 |傻瓜|表标记+--------+---------+|邮编 |标签标识 |+--------+---------+|1 |1 ||1 |2 ||1 |3 |

优点:

• 没有重复的标签名称.
• 更多的女孩会喜欢你.

缺点:更改标签的成本比方法 1 高.

解决方案

这些解决方案被称为 mysqlicious、scuttle 和 toxi.

这篇文章比较了每种方法的优缺点.

Related

Using SO as an example, what is the most sensible way to manage tags if you anticipate they will change often?

Way 1: Seriously denormalized (comma delimited)

table posts
+--------+-----------------+ 
| postId | tags            |
+--------+-----------------+
|   1    | c++,search,code |

Here tags are comma delimited.

Pros: Tags are retrieved at once with a single select query. Updating tags is simple. Easy and cheap to update.

Cons: Extra parsing on tag retrieval, difficult to count how many posts use which tags.

(alternatively, if limited to something like 5 tags)

table posts
+--------+-------+-------+-------+-------+-------+
| postId | tag_1 | tag_2 | tag_3 | tag_4 | tag_5 |
+--------+-------+-------+-------+-------+-------+
|   1    | c++   |search | code  |       |       | 

Way 2: "Slightly normalized" (separate table, no intersection)

table posts
+--------+-------------------+
| postId | title             |
+--------+-------------------+
|   1    | How do u tag?     |

table taggings
+--------+---------+
| postId | tagName |
+--------+---------+
|   1    | C++     |
|   1    | search  |

Pros: Easy to see tag counts (count(*) from taggings where tagName='C++').

Cons: tagName will likely be repeated many, many times.

Way 3: The cool kid's (normalized with intersection table)

table posts
+--------+---------------------------------------+
| postId | title                                 |
+--------+---------------------------------------+
|   1    | Why is a raven like a writing desk?   |

table tags
+--------+---------+
| tagId  | tagName |
+--------+---------+
|   1    | C++     |
|   2    | search  |
|   3    | foofle  |

table taggings
+--------+---------+
| postId | tagId   |
+--------+---------+
|   1    | 1       |
|   1    | 2       |
|   1    | 3       |

Pros:

• No repeating tag names.
• More girls will like you.

Cons: More expensive to change tags than way #1.

解决方案

These solutions are called mysqlicious, scuttle and toxi.

This article compares benefits and drawbacks of each.

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