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Annoying message when using mongodb

I use this code to use mongodb:

var mongo = require("mongodb"); var BSON = mongo.BSONPure; var server = new mongo.Server('localhost', 27017, {auto_reconnect: true, safe: true}); var db = new mongo.Db('dbname', server); db.open(function(err, db) { if(!err) { console.log("Connected to 'dbname' database"); db.collection("items", {safe:true}, function(err, collection) { console.log("Open database"); if (err) { console.log("The 'items' collection doesn't exist. Creating it with sample data."); var items = []; for (var i = 0; i < 10; i++) { items.push({ title: "title" + i, site_name: "site_name" + i, url: "url" + i, type: "type" + i, image: "image" + i }); } db.collection("items", function(err, collection) { collection.insert(items, {safe:true}, function(err, result) {}); }); } }); } });

When I launched the application, I received a message:

 ======================================================================================== = Please ensure that you set the default write concern for the database by setting = = one of the options = = = = w: (value of > -1 or the string 'majority'), where < 1 means = = no write acknowlegement = = journal: true/false, wait for flush to journal before acknowlegement = = fsync: true/false, wait for flush to file system before acknowlegement = = = = For backward compatibility safe is still supported and = = allows values of [true | false | {j:true} | {w:n, wtimeout:n} | {fsync:true}] = = the default value is false which means the driver receives does not = = return the information of the success/error of the insert/update/remove = = = = ex: new Db(new Server('localhost', 27017), {safe:false}) = = = = http://www.mongodb.org/display/DOCS/getLastError+Command = = = = The default of no acknowlegement will change in the very near future = = = = This message will disappear when the default safe is set on the driver Db = ========================================================================================

What is this message and how to fix it? Is there a better way to use mongodb?

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4 answers

Documents are available at

http://mongodb.github.com/node-mongodb-native/

use the MongoClient interface instead

http://mongodb.github.com/node-mongodb-native/driver-articles/mongoclient.html

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MongoDB helps you set the default write option (w) in the database settings.

Changing this line should do the trick

  var db = new mongo.Db('dbname', server, {w:1});

This will be good for development / hacking, but you should understand the consequences of this option before going into production.

MongoDB write a link to the conference

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The Db constructor has three arguments. "DataBaseName", ServerObject, {parameters}.

The displayed message is a warning about a problem with the recording and explains what parameters you received.

  var _mongodb = 'MyDataBase'; var db = new mongodb.Db(_mongodb, server, {w:'majority'});

Link: http://mongodb.imtqy.com/node-mongodb-native/api-generated/db.html

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 var MongoClient = require('mongodb').MongoClient, Server = require('mongodb').Server; var mongoClient = new MongoClient(new Server('localhost', 27017)); db = mongoClient.db("mydb"); db.open(function(err, db) { if(!err) { console.log("Connected to 'mydb' database"); db.collection('mycollection', {strict:true}, function(err, collection) { if (err) { console.log("error..."); } }); } });

Link: http://mongodb.imtqy.com/node-mongodb-native/api-generated/mongoclient.html

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