以第五范式表示三路数据库函数依赖
是否可以用第五范式表示非键列的复合键函数依赖？
我有三个表，
users
----------
id
name
events
----------
id
name
events_users
---------------------------
id
user_id
event_id
participation_type (ENUM)
据我所知，第五范式需要将表以自己的小实体表示。 所以我猜events_users表中的participation_type不能被称为第五范式？
谁能建议我一个更好的解决方案？
问题是，我一直在使用CodeIgniter的DataMapper库，其中每个表需要独立存在，即第五范式。
Is it possible to represent a composite key functional dependency of a non key column in fifth normal form?
I have three tables,
users
----------
id
name
events
----------
id
name
events_users
---------------------------
id
user_id
event_id
participation_type (ENUM)
As I know, the 5th normal form needs the tables to be represented in its own small entity. So i guess the participation_type in events_users table cannot be called a 5th normal form?
Can anyone suggest me a better solution?
The problem is, I've been using the DataMapper library of CodeIgniter where each table need to exist independently, ie 5th normal form.
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据我所知，您给出的示例已经是第五范式。
表中的列太少了，我看不到任何其他方式来排列它们！
据我所知，“participation_type”不会违反任何 NF 规则，因为没有其他列在语义上与其相关。
编辑回复评论：
也许正如您所建议的，这是 Datamapper/Codeigniter 的其他问题，与 5NF 无关。
如果您无法将字段添加到它生成的 user_events 表中，那么您可能需要抢占它并创建另一个实体，我们将其称为“出勤”（或模型中有意义的任何名称）。 出勤将具有以下字段：
然后告诉 Datamapper 出勤与用户和事件相关，并且它将生成（或要求您生成，或其他）两个链接表：
如果您按照这些方式执行某些操作，那么您将拥有一个您可以添加字段的考勤实体。
免责声明：我对 Datamapper 一无所知，我只是在这里阅读字里行间
As far as I can tell, the example you give is already in Fifth Normal Form.
You have so few columns in the tables that I can't see any other way to arrange them!
As far as I can tell, 'participation_type' does not break any NF rules because there are no other columns semantically related to it.
edit in response to comment:
Perhaps as you suggest this is some other problem with Datamapper/Codeigniter that is not related to 5NF.
If you cannot add fields into the user_events table that it generates, then perhaps you need to pre-empt it and create another entity, lets call it 'Attendance' (or whatever makes sense in your model). Attendance will have these fields:
Then tell Datamapper that Attendance is related to both Users and Events, and it will generate (or ask you to generate, or whatever) two linking tables:
If you do something along those lines, then you will have an Attendance entity that you can add fields to.
Disclaimer: I dont know anything about Datamapper, I'm just reading between the lines here