寻找猫鼬“你好世界”例子

Question

更新：已经有一段时间了。但当时决定不使用 Mongoose。主要原因是我们在使用 mongo 和 javascript 时无法真正找到使用 ORM 的充分理由。

---

我一直在尝试使用 Mongoose 创建一个数据库/模型，它基本上只是一个用户数据库，其中用户名是唯一的。听起来很简单，但由于某种原因我一直无法这样做。

到目前为止我得到的是：

var mongoose = require('mongoose').Mongoose,
    db = mongoose.connect('mongodb://localhost/db');

mongoose.model('User', {
    properties: [
        'name',
        'age'
    ],

    cast: {
        name: String,
        age: Number
    },

    //indexes: [[{name:1}, {unique:true}]],
    indexes: [
        'name'
    ]
    /*,
    setters: {},
    getters: {},
    methods: {}
    */
});    

var User = db.model('User');

var u = new User();
u.name = 'Foo';

u.save(function() {
    User.find().all(function(arr) {
        console.log(arr);
        console.log('length='+arr.length);
    });
});
/*User.remove({}, function() {});*/

它根本不起作用。数据库创建正常，但用户名不唯一。对我做错了什么有任何帮助或了解吗？

Answer 1

您应该在首次运行应用程序之前定义唯一索引。否则，您需要放弃您的收藏并重新开始。此外，当“user1”已存在时尝试保存 { name: 'user1' } 时，猫鼬不会抛出错误。

Answer 2

Learnboost 最近上传了一组示例 https://github.com/LearnBoost/mongoose/tree/大师/示例

Answer 3

我知道这个问题已有 10 年历史了，最初的发布者放弃了 Mongoose，但由于它突然出现在 Google 搜索的顶部附近，我觉得我会提供一个新的答案。

使用 Typescript 提供完整的基本示例。我已在评论中添加了
代码（如果适用）。

async function mongooseHelloWorld () {
    const url = 'mongodb://localhost/helloworld';

    // provide options to avoid a number of deprecation warnings
    // details at: https://mongoosejs.com/docs/connections.html
    const options = {
        'useNewUrlParser': true,
        'useCreateIndex': true,
        'useFindAndModify': false,
        'useUnifiedTopology': true
    };

    // connect to the database
    console.log(`Connecting to the database at ${url}`);
    await mongoose.connect(url, options);

    // create a schema, specifying the fields and also
    // indicating createdAt/updatedAt fields should be managed
    const userSchema = new mongoose.Schema({
        name:{
            type: String,
            required:true
        },
        email: {
            type: String,
            required: true
        }
    }, {
        timestamps: true
    });

    // this will use the main connection. If you need to use custom
    // connections see: https://mongoosejs.com/docs/models.html
    const User = mongoose.model('User', userSchema);

    // create two users (will not be unique on multiple runs)
    console.log('Creating some users');
    await User.create({ name: 'Jane Doe', email: '[email protected]' });
    await User.create({ name: 'Joe Bloggs', email: '[email protected]' });

    // Find all users in the database, without any query conditions
    const entries = await User.find();
    for (let i = 0; i < entries.length; i++) {
        const entry = entries[i] as any;
        console.log(`user: { name: ${entry.name}, email: ${entry.email} }`);
    }
}

// running the code, and making sure we output any fatal errors
mongooseHelloWorld()
    .then(() => process.exit(0))
    .catch(error => {
        console.log(error)
    });

请注意，这是在 Mongoose 5.9.26 上验证的，针对 Mongo 4.0.13 运行。

Answer 4

您需要定义架构。试试这个：（

var mongoose = require('mongoose').Mongoose,
db = mongoose.connect('mongodb://localhost/db'),
Schema = mongoose.Schema;

mongoose.model('User', new Schema({
    properties: [
        'name',
        'age'
    ],

    [...]
}));    

Answer 5

对于 Mongoose 2.7（在 Node v.0.8 中测试）：

var mongoose = require('mongoose'),
    Schema = mongoose.Schema;

var db = mongoose.connect('mongodb://localhost/db');

var User = new Schema({
  first_name: String,
  last_name: String
});

var UserModel = mongoose.model('User', User);

var record = new UserModel();

record.first_name = 'hello';
record.last_name = 'world';

record.save(function (err) {

  UserModel.find({}, function(err, users) {

    for (var i=0, counter=users.length; i < counter; i++) {

      var user = users[i];

      console.log( "User => _id: " + user._id + ", first_name: " + user.first_name + ", last_name: " + user.last_name );

    }

  });

});

Answer 6

尝试在 var mongoose = require('mongoose').Mongoose, 中给出正确的路径

。它对我有用..

#

我的代码

require.paths.unshift("/home/LearnBoost-mongoose-45a591d/mongoose");
var mongoose = require('mongoose').Mongoose;


var db = mongoose.connect('mongodb://localhost/db');


 mongoose.model('User', {
            properties: ['first name', 'last name', 'age', 'marriage_status', 'details', 'remark'],


});

var User = db.model('User');
var record = new User();

record.first name = 'xxx';
record.last name = 'xxx';
record.age = 'xxx';
record.marriage_status = 'xxx';
record.details = 'xxx';
record.remarks = 'xxx';

record.save(function() {
User.find().all(function(arr) {

   console.log(arr); 
   console.log('length='+arr.length);



});

}); 


//User.remove({}, function() {});

用 node filename.js 编译它
祝你好运..