索引和查询数组，使用cloudant和couchdb 2.0的芒果查询

本文介绍了索引和查询数组，使用cloudant和couchdb 2.0的芒果查询的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我具有以下数据库结构:

I have the following db structure:

{"_id": "0096874","genre": ["Adventure","Comedy", "Sci-Fi" ]} {"_id": "0099088","genre": ["Comedy", "Sci-Fi", "Western"]}

并希望像在mongodb中一样进行查询

and like to query it like I could do in mongodb

db.movies.find({genre: {$in: ["Comedy"]}})

当我在整个数据库中使用文本索引时，它可以工作，但这似乎非常浪费:

It works when i use a text index for the whole database, but that seems very wasteful:

// index { "index": {}, "type": "text" } //query { "selector": { "genre": { "$in": ["Comedy"] } }, "fields": [ "_id", "genre" ] }

以下索引不起作用:

{ "index": { "fields": [ "genre" ] }, "type": "json" }

什么是cloudant查询的正确索引，而不是整个数据库的索引? 谢谢您的帮助

What is the correct index for cloudant query, which does not index the whole db? Thanks for your help

推荐答案

您几乎完全正确.您的索引正确，但是您需要使用选择器来获取所有ID https ://cloudant/blog/mango-json-vs-text-indexes/.

You had it almost correct. Your index is right, but you need to throw in a selector to get all IDs cloudant/blog/mango-json-vs-text-indexes/.

正如Tony所说，这不是解决方案性能的好方法，

This isn't a great solution performance-wise, as Tony says,

之所以可行，是因为，Mango对所有文档执行上述$ in操作作为过滤机制.正如我们在上一节有关JSON语法的结论中所看到的，上述查询的性能折衷在于，它本质上执行完整索引扫描，然后应用过滤器.

{ "selector": { "_id": { "$gt": null }, "genre": { "$in": ["Western"] } }, "fields": [ "_id", "genre" ], "sort": [ { "_id": "asc" } ] }