recently learned about node on mdn, link there was a problem in creating a table structure. Running directly on the command line will report an error, as if caused by the & character in url, and the subsequent arguments are not recognized correctly. I...
question: there is a set of data similar to the following { "sn ": "18160481 ", "status ": 1, "updateTime ": 1542691932103} { "sn ": "18160482 ", "status ": 2, "updateTime ": 1542691932113} { "sn ": "18160483 ", "status ": 2, "updateTime ": ...
Boss, let me ask you a question. I have mongodb, locally and remotely. I use visualization tools to import local data into remote mongodb. The imported data of the remote mongodb can be found in both the visualization tool and the remote ssh. When I run ...
problem description Mongodb is successfully installed under Mac. Opening localhost:27017 shows that It looks like you are trying to access MongoDB over HTTP on the native driver port. command mongo can enter the database, and show dbs can displ...
requirement description: mongodb contains the main information of two collection,theme storage topics, as well as an array of product id. Now if you want to find out the details of the products in products through the detailed id of the product, how sh...
query conditions are composed of String and List, such as: (List < String > id, String location, String status,.) The exact number of fields in the parameter is not certain. There may be more than one . how to implement this situation? you d better ...
the operation of two-tier nesting is normal. db.collection.update({ xxx : xxx }, {$inc: { aaa.bbb : 1}}) but now if bbb is uncertain, it is a variable, such as let x = bbb ; db.collection.update({ xxx : xxx }, {$inc: {`aaa.${x}`: 1}}) ...
question: is it not recommended to use multi-table queries for mongodb non-relational databases? ...
before <host>1.1.1.1< host> <port>27017< port> <db>monitor< db> <collection>exception< collection> < connectionSource> < appender> s...
in the past, MySQL used to design er diagrams using powerdesigner,. Now it has been changed to mongodb. Is there any useful software for drawing er diagrams? ...
mongodb also seems to have the concept of connection pooling. The default maximum number of connections is 1024, and each connection consumes a certain amount of memory resources. How to understand this "connection " of mongobd? For example, in node,...
mongodb template query data is the time difference of field 1 minus field 2 by more than 30 minutes, and it is data within three days. Fields 1 and 2 are timestamps, how to write ...
the specific code is as follows: node beginners, excuse me const mongoose = require( mongoose ); mongoose.connect( mongodb: ) mongoose.model( content ,{}).find({}) .then( feeds =>{ console.log(feeds); }) the printed result ...
uses nodejs + mongoose the code is as follows const pkgInfo = await PkgModel.findOne({ _id }).populate({ path: cover , populate: { path: tag }, }).populate({ path: files , populate: { path: tag ...
there is a function that often needs to query data according to the factory id. Which of the following designs is more reasonable? or is the efficiency the same? scenario 1: { { "_id" : 1, "product" : "...
assertion src mongo db storage extent_manager.cpp:109 how to solve this error? ...
problem description there is a function of api: the information currently submitted is b and the database already has an information, that is, the specified task c (an and b are triggered regardless of order, and c is triggered as long as the combinat...
does your mongoDB sharding+replication cluster do Raid?? our cluster has 6 ssd. each ssd starts a mongod, and then makes a replication with the same disk on the other two servers. personal understanding of mongoDB is that the high reliability of d...
recently working on a node project, using mongoDB in the background. found that there is a default primary key _ id, in MongoDB. I can also set up a sequence myself, like mysql. if you use the default primary key, the returned JSON string uses _ id, wh...
db.mycollection.find () { "_ id ": ObjectId ( "5be2c9ebda9c816c79d9b531 "), "name ": "alex ", "id ": "888 ", "url ": [ "www.baidu.com ", "www.souhu.com "]} for example, how can I check the current url situation? Several url ...
I only know ajax,. Are there any other common methods, and where is the specific usage scenario? ...
I don t know how to add scrolling events ...
how do I click on a point to mark the color of the valid edges connected to that point? ...
problem description ask for advice in this code, when you choose the solution to join, you can choose to add the real and join the test. I think the real and the test code are the same. I would like to ask how to judge and execute the real and the tes...
use SpringMVC + mongodb to upload and download files. downloaded files cannot be opened except TXT (garbled code). 1. Suspected to be a problem with springmvc messageconverter configuration, tried to configure byteArrayConverter 2. Suspected to be...