CouchDB通过文档字段内部联接？ [英] CouchDB inner join by document field?

问题描述

我有一个问题，我有2种文档，其中一个像这样：

I have a question, i have 2 kind of documents, one of them is like this:

{
  "type": "PageType",
  "filename": "demo"
  "content": "zzz"
}

和另一个类似的东西：

{
  "type": "PageCommentType",
  "refFilename": "demo"
  "content": "some comment content"
}

我需要发出包含.comments字段的文档，该字段是我按条件PageType document filename == PageCommentType document refFilename字段链接的PageCommentType文档的数组。

i need to emit document that contains .comments field which is array of PageCommentType documents that i link on condition PageType document filename == PageCommentType document refFilename fields.

{
  "filename": "demo",
  "comments": [{}, {}, {}]
}

有人对如何实施有何建议？

Anyone has any suggestions on how to implement it?

谢谢。

推荐答案

您需要查看排序规则 。使用文件名作为键和类型标识符在同一个视图中发射两者，以区分注释和原始内容：

You need view collation. Emit both within the same view, using the filename as the key and a type identifier to discriminate between comments and the original content:

function(doc) {
  if (doc.type == "PageType") emit([doc.filename,0],doc.content);
  if (doc.type == "PageCommentType") emit[doc.refFilename,1],doc.content);
}

在查找文档 demo 及其注释，使用 startkey = [ demo，0] 和 endkey = [ demo，1] <运行查询/ code>：您将获得页面内容以及所有注释。

When looking for the document demo and its comments, run a query with startkey=["demo",0] and endkey=["demo",1]: you will get the page content followed by all the comments.

一旦拥有了所需的所有数据，但是它的格式格式不正确，您快完成了。只需编写 _list 函数即可读取所有行，并输出具有所需结构/架构的最终JSON文档。

Once you have all the data you want, but it's not in the right format, you are almost done. Simply write a _list function to read all the rows and output the final JSON document with the structure/schema that you need.

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