以 RESTful 方式重新排序项目 [英] Reordering items in a RESTful way
问题描述
我有一个包含以下数据的表:
I have a table that has the following data:
id position name
== ======== =========
1 4 Fred
2 2 Wilma
3 1 Pebbles
4 5 Barney
5 3 Betty
这是用于用户可以重新排列的列表(因此是位置列).我的问题是，我怎样才能以一种宁静的方式做到这一点.例如，如果我想将 Fred 移动到位置 2，我将如何发送请求?
This is for a list which the user can rearrange (hence the position column). My question is, how can I do this in a restful way. For example, if I want to move Fred to position 2, how would I send the request?
目前，我有这样的事情:
Currently, I have something like this:
PUT /user/1/reorder/2
这会将当前处于位置 4 的用户 1 (Fred) 移动到位置 2.SQL 代码还将运行一个查询，该查询将更改其他用户的位置以适应 Fred 的新位置.
This would move user 1 (Fred) who is currently in position 4 to position 2. The SQL code would also run a query that would change the position of the other users to adjust for Fred's new position.
执行此操作的正确 RESTful 方法是什么?
What is the proper RESTful way to do this?
推荐答案
为了有效地做到这一点，请使用哈希表并且从不重新排序所有内容，只需通过更改索引键将它们放在中间即可.什么意思?
In order to do it efficiently use a hash table and never reorder everything just put them in between by changing their index key. What do I mean?
让我们说
1 a
2 b
3 c
4 d
5 e
PUT /user/1/reorder/2
在我会做的里面，位置也是从索引中的位置导出的
Inside I would do, also the position is derived from the position in your index
1 2 b
2 2.5 a
3 3 c
4 4 d
5 5 e
正如 Kajow 所指出的，这种方法有两个问题:
As noted by Kajow, this approach has two issues:
多次重新排序后，浮点数可能不够
After multiple reorders, float numbers might not suffice
浮点数精度
解决它们:
我们不使用浮点数，而是使用大数字 100000、200000、300000 等并重新排序、200000、250000、30000 等
We don't use floats but big numbers 100000,200000,300000 etc and reorder, 200000,250000,30000,etc.
在 x 次重新订购后，我们重置为 100000,200000,300000,400000.可能有一种方法每 x 个分区只对小部分重新排序，以保持这个过程简单、小而零星
After x number of reorders we reset to 100000,200000,300000,400000. There might be a way to reorder only small parts every x divisions in order to keep this process simple, small and sporadic
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