mongodb

问题 I am currently working on a blogging app, in which users can create their own blogs and each blog has blogposts within that. I'm ideating about architecting a database that is scalable when each blog has a lot of blogposts. So is it better to structure my database as this: blog1 : { blogname : 'blog1', blogposts: [array of blogposts] }, blog2 : { blogname : 'blog2', blogposts: [array of blogposts] } Or should I create a separate collection with all the blogposts, something like this:

问题 I need to find a room by id and update received field to true where user id equals to xx . The document is here: { "_id" : ObjectId("5e5d0d870fc69641a41a3c65"), "users" : [ ObjectId("5e57d64d92cc878760086980"), ObjectId("5e57d64592cc87876008697e") ], "messages" : [ { "_id" : ObjectId("5e67834b6c8b2d356a4ad9fd"), "text" : "Hello", "user" : ObjectId("5e57d64d92cc878760086980"), "createdAt" : ISODate("2020-03-10T12:08:43.006Z"), "sent" : true, "received" : false }, { "_id" : ObjectId(

问题 This question already has answers here : Java MongoDB save multiple documents at once (4 answers) Closed 11 months ago . jdbcTemplate.batchUpdate("INSERT INTO TABLE_NAME (COL1, COL2, COL3) VALUES (?, ?, ?)", List<Object[]>); Is there a similar way that I can do same insert using MongoRepository Interfaces in Spring data mongodb and java ? 回答1: You can insert multiple documents into the collection using one of the following methods. Assuming a test collection and a Test.java POJO representng a

问题 A server is running multiple processes, process reads task from DB. Tasks contain status and _userid, which is external key for users collection. Look like like: { _userid: ObjectId(), status: 'waiting', date: Date() } Status can be: 'waiting', 'in progress', 'finished'. For every user I need tasks to run ordered by date and only one at a time. How can I build a query that selects one task: If nothing 'in progress', select first with status 'waiting' and update status to 'in progress'; If

问题 I have created a sample c# console application to connect to mongodb hosted on CentOS machine on a docker. The command used to create container is below: docker run -d --name mongodb-container -p 2020:27017 -v /home/mongodb_data:/var/lib/mongodb/data -v /home/mongodb_log:/var/log/mongodb -v /home/mongod.conf:/etc/mongod.conf -e MONGO_INITDB_ROOT_USERNAME=mongoadmin -e MONGO_INITDB_ROOT_PASSWORD=secret mongo System IP: 172.17.103.158 Mongodb docker port: 2020 Now coming to c# code class users

问题 Here is a bit of the code I have server.get("/get", getCallback); function getCallback(req,res) { collection.find({}).next(findCallback); function findCallback(err,foundRecord) { if (err == null) { console.log('FOUND: ' + foundRecord); return res.status(200).send(foundRecord); } else throw err; } } It give's me back {"readyState":1} in the console. No matter what I try it's giving me different types of errors. I have no problem-saving data to the collection but as soon as I go to take it out

问题 I have a MongoDB collection with 3 fields: _id: ObjectId field1: Number field2: Number I am doing this aggregation to get "distinct" field1/field2 rows and doing a total count of the results. This works OK in the client (Robo3t): db.mycollection.aggregate([ { $group: { _id: { field1: "$field1", field2: "$field2" }, } }, { $group: { _id: null, count: { $sum: 1 } } } ]) Result: { "_id" : null, "count" : 57.0 } How could I do this aggregation in Go using mongo-driver? There is this method to

问题 So I'm creating a data flow with Apache Airflow for grabbing some data that's stored in a Pandas Dataframe and then storing it into MongoDB. So I have two python methods, one for fetching the data and returning the dataframe and the other for storing it into the relevant database. How do I take the output of one task and feed it as the input to another task? This is what I have so far (summarized and condensed version) I looked into the concept of xcom pull and push and that's what I

问题 This question already has answers here : Retrieve only the queried element in an object array in MongoDB collection (14 answers) MongoDb query condition on comparing 2 fields (4 answers) Closed 10 months ago . Let's say I have the following document structure: { "A": { "_id": "ID0" }, "B": [ "a": { "_id": "ID0", "field": "X" }, "b": { "_id": "ID1", "field": "Y" } ] } I want to project B matched with the _id in A . The end result would be: { "B": [ "a": { "_id": "ID0", "field": "X" } ] } I

问题 Error retrieving user information with redux. I want to get the user information (name, password and address of the avatar from the db) and then edit it. I'm using nodejs, express, react, redux and jwt. Actions/user.js import axios from 'axios'; import {setAlert} from './alert'; import {GET_USER, USER_ERROR} from './types'; //Get current users profile export const getCurrentUser = () => async dispatch => { try { const res = await axios.get('/api/users/me'); dispatch({ type: GET_USER, payload: