mongodb-query

问题 I want to find all zone data with "AHU":"C". First, I query without projection and get these. > db.buildings.find({"zone.AHU": "C"}).pretty() { "_id" : ObjectId("5aba4460a042dc4a2fdf26cd"), "name" : "Test Street", "coordinate" : [ 12, 31 ], "yearlyEnergyCost" : 1444, "zone" : [ { "name" : "AHU-C-Z2", "_id" : ObjectId("5aba4460a042dc4a2fdf26ce"), "AHU" : "C", "precooling" : [ ], "subZone" : [ ] }, { "name" : "AHU-D-Z1", "_id" : ObjectId("5abc7528100730697163a3ab"), "AHU" : "D", "precooling" :

问题 I want to find all zone data with "AHU":"C". First, I query without projection and get these. > db.buildings.find({"zone.AHU": "C"}).pretty() { "_id" : ObjectId("5aba4460a042dc4a2fdf26cd"), "name" : "Test Street", "coordinate" : [ 12, 31 ], "yearlyEnergyCost" : 1444, "zone" : [ { "name" : "AHU-C-Z2", "_id" : ObjectId("5aba4460a042dc4a2fdf26ce"), "AHU" : "C", "precooling" : [ ], "subZone" : [ ] }, { "name" : "AHU-D-Z1", "_id" : ObjectId("5abc7528100730697163a3ab"), "AHU" : "D", "precooling" :

问题 I want to find all zone data with "AHU":"C". First, I query without projection and get these. > db.buildings.find({"zone.AHU": "C"}).pretty() { "_id" : ObjectId("5aba4460a042dc4a2fdf26cd"), "name" : "Test Street", "coordinate" : [ 12, 31 ], "yearlyEnergyCost" : 1444, "zone" : [ { "name" : "AHU-C-Z2", "_id" : ObjectId("5aba4460a042dc4a2fdf26ce"), "AHU" : "C", "precooling" : [ ], "subZone" : [ ] }, { "name" : "AHU-D-Z1", "_id" : ObjectId("5abc7528100730697163a3ab"), "AHU" : "D", "precooling" :

问题 I find my document from whole collection like this: const account = await Account.findOne({ "buildings.gateways.devices.verificationCode": code }) const buildings = account.buildings const gateways = buildings[0].gateways; const devices = gateways[0].devices; const device = _.filter(devices, d => d.verificationCode === code); now I want to change one of the property "patientLastName" and then save the whole document. I am doing as below. device.patientLastName = lastName; const updated =

问题 Supposed I have a mongo document that looks similar to the following: { 'foo':1 'listOfLists' : [ [1,2],[3,4] ] } (Yes I am aware this isn't how it "really" looks but it should be simple enough for explanation purposes.) If I wanted to write a query that would check to see if the listsOfLists list object contains the combination of [3,4], how could I go about doing that? Could I do something like collection.find({'listsOfLists' : {'$elemMatch' : [3,4] } }) 回答1: collection.find({ 'listsOfLists

问题 I have a MongoDB document that is structured similar to the structure below follows. I am searching based on people.search_columns.surname and people.columns.givenname. So for example, when I search for the given name of "Valentine", I want to get the document back, but Nicholas Barsaloux should not be included. Data structure: [_id] => MongoId Object ( [$id] => 53b1b1ab72f4f852140dbdc9 ) [name] => People From 1921 [people] => Array ( [0] => Array ( [name] => Barada, Valentine [search_columns

问题 I have simple collection. I want to push item in question, but it gives an exception.How can I resolve it ? /* 1 */ my collection data { "_id" : ObjectId("557e8c93a6df1a22041e0879"), "QuestionCount" : 2.0000000000000000, "Questions" : [ { "_id" : ObjectId("557e8c9ba6df1a22041e087a"), "DataSource" : [], "DataSourceItemCount" : NumberLong(0) }, { "_id" : ObjectId("557e8c9fa6df1a22041e087b"), "DataSource" : [], "DataSourceItemCount" : NumberLong(0) } ], "Name" : "er" } ( id

问题 According to Mongo Documentation, The { item : null } query matches documents that either contain the item field whose value is null or that do not contain the item field. I can't find documentation for this, but as far as I can tell, both cases (value is null or field is missing) are stored in the index as null . So if I do db.orders.createIndex({item: 1}) and then db.orders.find({item: null}) , I would expect an IXSCAN to find all documents that either contain the item field whose value is

问题 According to Mongo Documentation, The { item : null } query matches documents that either contain the item field whose value is null or that do not contain the item field. I can't find documentation for this, but as far as I can tell, both cases (value is null or field is missing) are stored in the index as null . So if I do db.orders.createIndex({item: 1}) and then db.orders.find({item: null}) , I would expect an IXSCAN to find all documents that either contain the item field whose value is

问题 I am trying to implement a simple raffling system where I do a GET /test which returns a random user who (1) hasn't won the raffle previously and (2)registered in the past hour. In Mongo, there may be multiple documents associated with a user since the user can sign up for multiple subjects. For example {id: 1, name: 'John', subject: 'math',...} and {id: 1, name: 'John', subject: 'english',...} . If John gets picked for the raffle for math, then he will be ineligible for all subsequent