从 node.js 在 mongolab mongodb 数据库中创建集合模式
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Creating a collection schema in a mongolab mongodb database from node.js
提问by RBR
I'm new to node.js and mongodb.
我是 node.js 和 mongodb 的新手。
I'm trying to create a schema for a User collection in a mongolab mongodb database from a node.js app with the code below. The code does not seem to be failing (at least, I get no error messages), but I don't see any indication that it is succeeding either. That is, when I go to mongolab and look at my database, I don't see that any schema was created - https://dzwonsemrish7.cloudfront.net/items/01263Y1c312s233V0R17/mongodb-schema.png?v=7fdc20e3.
我正在尝试使用以下代码从 node.js 应用程序为 mongolab mongodb 数据库中的用户集合创建模式。代码似乎没有失败（至少，我没有收到错误消息），但我也没有看到任何成功的迹象。也就是说，当我去 mongolab 并查看我的数据库时，我没有看到创建了任何架构 - https://dzwonsemrish7.cloudfront.net/items/01263Y1c312s233V0R17/mongodb-schema.png?v=7fdc20e3。
Can someone explain what I might be doing wrong, or how I can verify that my code succeeded and a schema was, in fact, created for my collection?
有人可以解释我可能做错了什么，或者我如何验证我的代码是否成功并且实际上为我的集合创建了模式？
// file: app.js
var express = require('express'),
http = require('http'),
mongoose = require('mongoose');
var app = express(),
port = 3000;
// Connect to database in the cloud (mongolab)
mongoose.connect('mongodb://username:[email protected]:41344/stockmarket');
// Create a schema for User collection
mongoose.connection.on('open', function () {
console.log(">>> Connected!");
var UserSchema = new mongoose.Schema({
username: {type: String, unique: true},
password: String
});
var UserModel = mongoose.model('User', UserSchema);
});
app.get('/', function(req, res){
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello, World!\n');
});
http.createServer(app).listen(port, function(){
console.log("Express server listening on port " + port + " ...");
});
回答by Brian Cajes
You must insert a document first. Schemas are not explicitly defined in mongodb. Once you insert a document, the collection will automatically be created and you will see it in the mongolab console.
您必须先插入文档。模式在 mongodb 中没有明确定义。插入文档后，将自动创建集合，您将在 mongolab 控制台中看到它。
Example from http://mongoosejs.com/
var mongoose = require('mongoose');
var db = mongoose.createConnection('localhost', 'test');
var schema = mongoose.Schema({ name: 'string' });
var Cat = db.model('Cat', schema);
var kitty = new Cat({ name: 'Zildjian' });
kitty.save(function (err) {
if (err) // ...
console.log('meow');
});
after the save call above the collection will be created
在上面的保存调用之后，将创建集合
回答by Shyam Bhagat
Data in MongoDB has a flexible schema. Documents in the same collection do not need to have the same set of fields or structure, and common fields in a collection's documents may hold different types of data.
MongoDB 中的数据具有灵活的模式。同一集合中的文档不需要具有相同的字段集或结构，并且集合文档中的公共字段可能包含不同类型的数据。
