结合2 MongoDB集合对象下划线或其他东西

Combining 2 MongoDB collection objects with underscore or something else?

本文关键字：线或 其他 MongoDB 集合 对象 结合      更新时间：2023-09-26

我正在对所有comments和commentLikes进行查询。本质上，我在我的视图中循环评论集合，但是我需要将commentLikes与comments联系起来。目前commentLikes对comments._id的引用为commentLikes.comment_id。

我正在考虑使用下划线，因为这里看起来有一些不错的实用程序函数，但我会使用哪些?我最终玩了_.where，但我不确定这是否是工作的正确工具。

这是最好的方法吗?

var comments = 
[ { submission_id: '513d3702b99f8b1ca5000026',
    comment: 'asdfnasdfoiasdfiosdaf',
    user_id: '1',
    _id: '5157e79c562277e457000011',
    deleted: false,
    created: 'Sun Mar 31 2013 00:37:00 GMT-0700 (PDT)',
    parent_id: null },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment: 'asdfioasdfoiasdjiofasdijofjiasodf',
    user_id: '1',
    _id: '5157e799562277e457000010',
    deleted: false,
    created: 'Sun Mar 31 2013 00:36:57 GMT-0700 (PDT)',
    parent_id: null },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment: 'sdafijsadjiofasoijfjaiosdfjioasdfjiosdaf',
    user_id: '1',
    _id: '5157e797562277e45700000f',
    deleted: false,
    created: 'Sun Mar 31 2013 00:36:55 GMT-0700 (PDT)',
    parent_id: null },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment: 'asdfjiadsfojidfsjoaifdaijofdasijods',
    user_id: '1',
    _id: '5157e794562277e45700000e',
    deleted: false,
    created: 'Sun Mar 31 2013 00:36:52 GMT-0700 (PDT)',
    parent_id: null },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment: 'asdfiasdfijoasdfoijas',
    user_id: '1',
    _id: '5157e40227bf651157000280',
    deleted: false,
    created: 'Sun Mar 31 2013 00:21:38 GMT-0700 (PDT)',
    parent_id: null } ];
var commentLikes =
    [ { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e40227bf651157000280',
    user_id: 1,
    _id: '5157e40527bf651157000286',
    created: 'Sun Mar 31 2013 00:21:41 GMT-0700 (PDT)' },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e40227bf651157000280',
    user_id: 1,
    _id: '5157e40b27bf65115700028e',
    created: 'Sun Mar 31 2013 00:21:47 GMT-0700 (PDT)' },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e797562277e45700000f',
    user_id: 1,
    _id: '5157e7cc9c1fe3ed57000001',
    created: 'Sun Mar 31 2013 00:37:48 GMT-0700 (PDT)' },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e799562277e457000010',
    user_id: 1,
    _id: '5157e7cd9c1fe3ed57000002',
    created: 'Sun Mar 31 2013 00:37:49 GMT-0700 (PDT)' },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e79c562277e457000011',
    user_id: 1,
    _id: '5157e7ce9c1fe3ed57000003',
    created: 'Sun Mar 31 2013 00:37:50 GMT-0700 (PDT)' },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e79c562277e457000011',
    user_id: 1,
    _id: '5157e7d19c1fe3ed57000004',
    created: 'Sun Mar 31 2013 00:37:53 GMT-0700 (PDT)' },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e79c562277e457000011',
    user_id: 1,
    _id: '5157e7d29c1fe3ed57000005',
    created: 'Sun Mar 31 2013 00:37:54 GMT-0700 (PDT)' },
  { submission_id: '513d3702b99f8b1ca5000026',
    comment_id: '5157e79c562277e457000011',
    user_id: 1,
    _id: '5157e7d29c1fe3ed57000006',
    created: 'Sun Mar 31 2013 00:37:54 GMT-0700 (PDT)' } ];
var newCommentObj = comments;
_.map(newCommentObj, function(key) {
    // get commentLikes for each comment
    var commentId = key._id,
        likes = _.where(commentLikes, {comment_id : commentId});
});

如果没有，我应该怎么做?对于多个Mongoose集合，正确的方法是什么?我来自传统的MySQL背景，所以没有关联是我习惯的事情。

您可以使用下划线的groupBy和map来完成，这里是工作示例。

你也可以在"mongodb"中使用mapReduce来组合你的集合，在这里查看更多细节。

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