当存在与每条信息相关联的可变数量的标签时，在关系数据库中存储标签的良好方式 [英] good way to store tags in relational database when there are variable numbers of tags associated with each piece of information

问题描述

我想在SQL关系数据库中存储可以用变量标签标记的句子。所以，我可能有一个句子，如

 '太阳慢慢地在西方，我们向你提出了一个很好的告别。 '
  

标记以下标记：

 'farewell'，'goodbye'，'amiable'
  

句子的标签数量可以不同。在这里给出的例子中，有三个标签。

在关系数据库中组织这种类型的信息是一种明智的方法？

解决方案

你有一个多对多的关系。创建三个表：句，标签和 sentence_tag 。 句和标签每个都有一个主键 id 字段和 sentence_tag 将有 sentence_id 字段和 tag_id 字段。要查找 id = $ sID 的句子标签，

  SELECT tag_name FROM tags WHERE id IN（SELECT tag_id FROM sentence_tag WHERE sentence_id = $ sID）; 
  

I want to store sentences that can be tagged with variable numbers of tags in an SQL relational database. So, I may have a sentence such as

'As the sun sets slowly in the west, we bid you a fine farewell.'

tagged with the following tags:

'farewell', 'goodbye', 'amiable'

The number of tags for a sentence can vary. In the example given here, there are three tags.

What would be a sensible way to organise this type of information in a relational database? What tables etc. would be reasonable?

Thanks!

解决方案

You have a many-to-many relationship. Make three tables: sentence, tag and sentence_tag. The sentence and tag tables will each have a primary key id field and sentence_tag will have a sentence_id field and a tag_id field. To find the tags for a sentence with id = $sID,

SELECT tag_name FROM tags WHERE id IN (SELECT tag_id FROM sentence_tag WHERE sentence_id = $sID);

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