mongodb

问题 I am working on some test program for SpringData MongoDB , I have done it same as it's mentioned on http://static.springsource.org/spring-data/data-document/docs/1.0.0.M2/reference/html/#mongo.core. But it's showing exceptions: package com.springMongo.core; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import org

问题 I am trying to design my database model and i dont have clue how to fit array of strings and array of objects into it. My current model is: const mongoose = require("mongoose"); const Schema = mongoose.Schema; const schema = new Schema({ email: { type: String, unique: true, required: true }, hash: { type: String, required: true }, createdDate: { type: Date, default: Date.now }, settings: { favorites: { /* ??? */ }, cart: { /* ??? */ }, states: { favorites: { type: Boolean, default: true },

问题 How to control the size of large journals files as journal file take large amount of space. How can the space can be saved using small files. 回答1: After doing some research: Setting smallfiles option for controlling journaling doesn't control the size However the command is --smallfiles 回答2: Here are some ways to control journal file size, Use --smallfiles option in mongod which will use 128MB as max size of journal file instead of 1GB ulimit is way in unix to control system settings. It will

问题 Here is my code in model.js file: const mongoose = require("mongoose"); const con = require("./connection"); con(); const schoolNotices = mongoose.model("schoolNotices", { title:{ type: String }, date:{ type:String }, details:{ type:String } }); module.exports = schoolNotices; And I have imported this code into students.js file router.route("/notices") .get((req,res)=>{ schoolNotices.find({},(err,docs)=>{ if(err){ return console.log(err) } res.render("studentNotices",{title:"Notices",data

问题 Currently, we have an orderId for which we give the benefit(posting) to the user. There are multiple events that can trigger benefit/posting. But the condition is that only 1 event should be triggered. Hence for handling current requests, we created a boolean field POSTING_EVENT_SENT , initially set to false, and later whoever was able to mark it as true can proceed further. public boolean isOrderLockedAndUpdatedToTriggerPosting(String orderId, OrderStatus orderStatus) { Query query = new

问题 I have a problem joining two collections in mongoose. I have two collections namely: student and exams. Student model: { fullname: { type: String, required: true }, email: { type: String, required: true }, } Exams model: { test: { type: String, required: false }, top10: [ type: { studentId: { type: String, required: true }, score: { type: Number, required: false }, } ] } Now, I want to join them two by studentId . The result should be: { "test": "Sample Test #1", "students": [ { "studentId":

问题 Currently, we have an orderId for which we give the benefit(posting) to the user. There are multiple events that can trigger benefit/posting. But the condition is that only 1 event should be triggered. Hence for handling current requests, we created a boolean field POSTING_EVENT_SENT , initially set to false, and later whoever was able to mark it as true can proceed further. public boolean isOrderLockedAndUpdatedToTriggerPosting(String orderId, OrderStatus orderStatus) { Query query = new

问题 I have a problem joining two collections in mongoose. I have two collections namely: student and exams. Student model: { fullname: { type: String, required: true }, email: { type: String, required: true }, } Exams model: { test: { type: String, required: false }, top10: [ type: { studentId: { type: String, required: true }, score: { type: Number, required: false }, } ] } Now, I want to join them two by studentId . The result should be: { "test": "Sample Test #1", "students": [ { "studentId":

问题 Sorry for my bad English. I have a table in postgres like: CREATE TABLE report ( id serial primary key, sensor_id integer, datetime timestamp, ...(many other fields) ); Collection in mongo stores the same data. Index in Postgres (I created all of them and separatly, but result is the same) : create index report_datetime on report (datetime desc); create index report_sensor_datetime on report (datetime desc, sensor_id); create index report_sensor_datetime_1 on report (sensor_id, datetime desc)

问题 Sorry for my bad English. I have a table in postgres like: CREATE TABLE report ( id serial primary key, sensor_id integer, datetime timestamp, ...(many other fields) ); Collection in mongo stores the same data. Index in Postgres (I created all of them and separatly, but result is the same) : create index report_datetime on report (datetime desc); create index report_sensor_datetime on report (datetime desc, sensor_id); create index report_sensor_datetime_1 on report (sensor_id, datetime desc)