Node.js 使用mongodb时的恼人消息

我使用此代码是为了使用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) {});
                });
            }
        });
    }
});

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（函数（err，db）{
如果（！err）{
log（“连接到'dbname'数据库”）；
collection（“items”，{safe:true}，函数（err，collection）{
log（“开放数据库”）；
如果（错误）{
log（“items”集合不存在。使用示例数据创建它。”）；
var项目=[]；
对于（变量i=0；i<10；i++）{
推({
标题：“标题”+i，
站点名称：“站点名称”+i，
url:“url”+i，
类型：“类型”+i，
图像：“图像”+i
});
}
db.集合（“项”，函数（错误，集合）{
insert（项，{safe:true}，函数（err，result）{}）；
});
}
});
}
});

运行应用程序时，我收到以下消息：

========================================================================================
=  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           =
========================================================================================

========================================================================================
=请确保通过设置=
=其中一个选项=
=                                                                                      =
=w：（值>-1或字符串“多数”），其中<1表示=
=无写入确认=
=日记账：真/假，在确认前等待刷新日记账=
=fsync:true/false，在确认之前等待文件系统刷新=
=                                                                                      =
=对于向后兼容性，仍然支持safe，并且=
=允许值为[true | false |{j:true}{w:n，wtimeout:n}{fsync:true}]=
=默认值为false，这意味着驱动程序未收到=
=返回插入/更新/删除成功/错误的信息=
=                                                                                      =
=ex:new Db（新服务器（'localhost'，27017），{safe:false}）=
=                                                                                      =
=   http://www.mongodb.org/display/DOCS/getLastError+命令=
=                                                                                      =
=无确认默认值将在不久的将来更改=
=                                                                                      =
=当在驱动程序数据库上设置默认安全设置时，此消息将消失=
========================================================================================

此消息是什么？我如何修复它？

---

是否有更好的方法使用mongodb？

文档可在

改用MongoClient接口

---

MongoDB正在帮助您在其DB设置中设置默认写关注点（w）参数

换一行就行了

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

这对于开发/黑客来说很好，但在投入生产之前，您应该了解此选项的后果

---

Db构造函数有三个参数。“DataBaseName”，ServerObject，{parameters}

显示的消息是关于写入问题的警告，并解释了您得到的选项

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

参考：

---

Ref:

lead here得到同样的错误，在我的情况下指向文档并没有多大帮助。请参阅

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...");

        }
    });
}
});