Mongoose API : http://mongoosejs.com/docs/api.html

// mongoose 链接
var mongoose = require('mongoose');
var db       = mongoose.createConnection('mongodb://127.0.0.1:27017/NodeJS'); 

// 链接错误
db.on('error', function(error) {
    console.log(error);
});

// Schema 结构
var mongooseSchema = new mongoose.Schema({
    username : {type : String, default : '匿名用户'},
    title    : {type : String},
    content  : {type : String},
    time     : {type : Date, default: Date.now},
    age      : {type : Number}
});

// 添加 mongoose 实例方法
mongooseSchema.methods.findbyusername = function(username, callback) {
    return this.model('mongoose').find({username: username}, callback);
}

// 添加 mongoose 静态方法，静态方法在Model层就能使用
mongooseSchema.statics.findbytitle = function(title, callback) {
    return this.model('mongoose').find({title: title}, callback);
}

// model
var mongooseModel = db.model('mongoose', mongooseSchema);

// 增加记录 基于 entity 操作
var doc = {username : 'emtity_demo_username', title : 'emtity_demo_title', content : 'emtity_demo_content'};
var mongooseEntity = new mongooseModel(doc);
mongooseEntity.save(function(error) {
    if(error) {
        console.log(error);
    } else {
        console.log('saved OK!');
    }
    // 关闭数据库链接
    db.close();
});

// 增加记录 基于model操作
var doc = {username : 'model_demo_username', title : 'model_demo_title', content : 'model_demo_content'};
mongooseModel.create(doc, function(error){
    if(error) {
        console.log(error);
    } else {
        console.log('save ok');
    }
    // 关闭数据库链接
    db.close();
});

// 修改记录
mongooseModel.update(conditions, update, options, callback);
var conditions = {username : 'model_demo_username'};
var update     = {$set : {age : 27, title : 'model_demo_title_update'}};
var options    = {upsert : true};
mongooseModel.update(conditions, update, options, function(error){
    if(error) {
        console.log(error);
    } else {
        console.log('update ok!');
    }
    //关闭数据库链接
    db.close();
});

// 查询
// 基于实例方法的查询
var mongooseEntity = new mongooseModel({});
mongooseEntity.findbyusername('model_demo_username', function(error, result){
    if(error) {
        console.log(error);
    } else {
        console.log(result);
    }
    //关闭数据库链接
    db.close();
});

// 基于静态方法的查询
mongooseModel.findbytitle('emtity_demo_title', function(error, result){
    if(error) {
        console.log(error);
    } else {
        console.log(result);
    }
    //关闭数据库链接
    db.close();
});

// mongoose find
var criteria = {title : 'emtity_demo_title'}; // 查询条件
var fields   = {title : 1, content : 1, time : 1}; // 待返回的字段
var options  = {};
mongooseModel.find(criteria, fields, options, function(error, result){
    if(error) {
        console.log(error);
    } else {
        console.log(result);
    }
    //关闭数据库链接
    db.close();
});

// 删除记录
var conditions = {username: 'emtity_demo_username'};
mongooseModel.remove(conditions, function(error){
    if(error) {
        console.log(error);
    } else {
        console.log('delete ok!');
    }

    //关闭数据库链接
    db.close();
});