mongodb-query

问题 Currently my User model looks like: { _id: 'SomeId' firstName: 'John', lastName: 'Cena', books: [ { _id: 'xyz', title: 'a', author:'b', ratings:[ {source:'source1', value:"8"}, {source:'source2', value:"9"}] }, { _id: 'abc', title: 'c', author:'d', ratings:[ {source:'source3', value:"7"}, {source:'source4', value:"5"}] } ] } After making an findOneAndUpdate query to update rating=>value of 1st book object(_id: "xyz") from 8 to 10 for a given source(say "source1") : let up={ 'books.$[book]

问题 So I have a MongoDB instance where I am trying to update data in one collection with data from another collection. The two collections are participants with about 180k documents and questions with about 95k documents. Documents in participants typically look something like this: { "_id" : ObjectId("52f90b8bbab16dd8594b82b4"), "answers" : [ { "_id" : ObjectId("52f90b8bbab16dd8594b82b9"), "question_id" : 2081, "sub_id" : null, "values" : [ "Yes" ] }, { "_id" : ObjectId("52f90b8bbab16dd8594b82b8

问题 Hi i'm having a discussion object collection and a user deatils collection. Discussion collection stores the participants username in an array of strings. Discussion collection is as follows: [{ "_id": "5a4dbdaab46b426863e7ead3", "topic": "test", "topicDesc": "test123", "createdOn": "2018-01-04T05:37:46.088Z", "participants": ["akhil","ben"] //[usernames] }] The user details collection is as follows: [{ "_id": "59e6d6ba02e11e1814481022", "username": "ben", "name": "Ben S", "email": "qwerty

问题 I have a collection with a structure similar to this. { "_id" : ObjectId("59d7cd63dc2c91e740afcdb"), "dateJoined": ISODate("2014-12-28T16:37:17.984Z"), "activatedMonth": 5, "enrollments" : [ { "month":-10, "enrolled":'00'}, { "month":-9, "enrolled":'00'}, { "month":-8, "enrolled":'01'}, //other months { "month":8, "enrolled":'11'}, { "month":9, "enrolled":'11'}, { "month":10, "enrolled":'00'} ] } month in enrollments sub document is a relative month from dateJoined. activatedMonth is a month

问题 Suppse I created index like following :- db.collection.createIndex( { propA: 1, propB: 1, propC:1 } ) and I query like following :- db.collection.find({propB:'x', propC: 'y', propA:'z'}) will mongo query engine use the index created above or not. Does sequence of key matters in usage of compound index while writing query? 回答1: The order of keys in a query doesn't matter: MongoDB is smart enough to look at all the queried properties and find a suitable index. However, the order of keys defined

问题 I would like to view all the created users Meteor.users.find().fetch() that were created in the database between the beginning of 1st September and the end of 30th September. How do I achieve this in code. Find inline my failed attempt: var beginningOfMonth = new Date(); beginningOfMonth.setMonth(8, 1); console.log("beginning Of the Month: "+beginningOfMonth); The code above yeilds: beginning Of the Month: Sat Sep 01 2018 21:44:00 GMT+0300 (East Africa Time) ... var endOfMonth = new Date();

问题 I've got a collection of questions. Each question has an array of answers. Each answer has an array of votes in the form of user id's. Here is an sample question: { "_id" : "PeD7YxzPdbm9MM6rQ", "answers" : [ { "_id" : "481f791b003ffc58f2adf200", "answer" : "d1", "votes" : [] }, { "_id" : "cdf02143fa7a10e939df636b", "answer" : "d2", "votes" : [ "USER1" ] }, { "_id" : "4d552e31fd45a9b2b25e2e3a", "answer" : "d3", "votes" : [ "USER2" ] } ] } I've replaced the IDs "RdqMhRkboWzfxNt8a" with USER1

问题 I am trying to get subdocuments which are matched my conditions. My MongoDB query like that: db.SCSIssue.find( { _id: ObjectId("5439a2992ea8cc0f70feef2d") }, { Statuses: { $elemMatch: { StatusID: { $gte : NumberLong(521055087020736513) } } } } ) My schema like that: { .... "_id": ObjectId("5439a2992ea8cc0f70feef2d"), .... "Statuses": [{ .... "StatusID": NumberLong(525623822633172993), },{ .... "StatusID": NumberLong(521055087020736513), },{ .... "StatusID": NumberLong(521060802959532033), }]

问题 I wonder know how to return the specified embedded keys ? by the similar query db.collection.find({"table_name": "change_in_real_gdp", {"data.*.actual":1, "data.*. upper_end_of_range"}}) Original document { "_id": "2012-06-20_change_in_real_gdp", "table_name": "change_in_real_gdp", "data": { "2007": { "actual": "4.8", "upper_end_of_range": "-", "upper_end_of_central_tendency": "-", "lower_end_of_central_tendency": "-", "lower_end_of_range": "-" }, "2008": { "actual": "6.9", "upper_end_of

问题 I'm querying a mongo database to retrieve the tiles for the display in rougelike game. This is the function I use: function get_display(){ var collections = ['austinsroom']; var db = mongojs(uri, collections); var temphtml = ''; for(var j = 0; j < 3; j++) { console.log("y=" + String(j)); db.austinsroom.find({"y": j}, {}).sort({"x": 1}, function(err, records) { if(err) { console.log("There was an error executing the database query."); return; } var i = records.length; while(i--) { temphtml +=