Javascript DynamoDB（dynamoose）-类型错误：model.save不是函数

我正在使用dynamoose从node.js访问DynamoDB

我正在node.js中使用swagger实现一个crudapi，并且在更新（put）endoint时遇到了困难。它应该非常类似于POST端点，顺便说一句，它工作得很好

我已经定义了一个dynamoose模式，并基于该模式导出了一个dynamoose模型

然后，我实现了一个控制器模块，它导入模型并使用dynamooseapi模型函数处理数据库。这段代码显示了如何在控制器中实现post方法：

'use strict';

// my-model.js exports the model
var MyModel = require('../models/my-model');

var MyController = {

       postMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.body.attr1; // primary key
                myModel.attr2 = req.body.attr2;

                myModel.save(function(err, myModelStored) {
                        if (err) {
                                console.log("Error storing InvoiceConfig");

                                res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelStored);
                });
       }
}

module.exports = MyController;

'use strict';

// my-model.js exports the model
var MyModel = require('../models/my-model');

var MyController = {

       updateMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.swagger.params.id.value;  // Primary key
                myModel.attr2 = req.body.attr2;

                // Overwrites the object in the DB
                myModel.save(function(err, myModelUpdated) {
                        if (err) {
                            console.log("Error in update method");
                            res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelUpdated);
                });
       },

       postMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.body.attr1; // primary key
                myModel.attr2 = req.body.attr2;

                myModel.save(function(err, myModelStored) {
                        if (err) {
                                console.log("Error in post method");
                                res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelStored);
                });
       }
}

module.exports = MyController;

TypeError: myModel.save is not a function
    at updateMyObject (/home/user/my-server/api/controllers/my-controller.js:15:17)

如您所见，在控制器的post方法中，实例化了一个模型，根据post请求主体中接收的参数设置了属性，最后调用该方法将模型存储在数据库中。这很有效

现在，我想向我的控制器添加一个更新方法，以更新存储在数据库中的一个项的属性。根据dynAmoose API文档，“将项放在DynamoDB表中并覆盖该项”。这意味着我可以将它用于我的更新方法，我传递整个对象（包括更新的属性），它将用指定的主键覆盖对象

据此，我在控制器中实现更新方法：

'use strict';

// my-model.js exports the model
var MyModel = require('../models/my-model');

var MyController = {

       postMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.body.attr1; // primary key
                myModel.attr2 = req.body.attr2;

                myModel.save(function(err, myModelStored) {
                        if (err) {
                                console.log("Error storing InvoiceConfig");

                                res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelStored);
                });
       }
}

module.exports = MyController;

'use strict';

// my-model.js exports the model
var MyModel = require('../models/my-model');

var MyController = {

       updateMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.swagger.params.id.value;  // Primary key
                myModel.attr2 = req.body.attr2;

                // Overwrites the object in the DB
                myModel.save(function(err, myModelUpdated) {
                        if (err) {
                            console.log("Error in update method");
                            res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelUpdated);
                });
       },

       postMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.body.attr1; // primary key
                myModel.attr2 = req.body.attr2;

                myModel.save(function(err, myModelStored) {
                        if (err) {
                                console.log("Error in post method");
                                res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelStored);
                });
       }
}

module.exports = MyController;

TypeError: myModel.save is not a function
    at updateMyObject (/home/user/my-server/api/controllers/my-controller.js:15:17)

但当我尝试发送数据库中某个项目的PUT（更新）请求时，控制器的更新方法中出现以下错误：

'use strict';

// my-model.js exports the model
var MyModel = require('../models/my-model');

var MyController = {

       postMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.body.attr1; // primary key
                myModel.attr2 = req.body.attr2;

                myModel.save(function(err, myModelStored) {
                        if (err) {
                                console.log("Error storing InvoiceConfig");

                                res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelStored);
                });
       }
}

module.exports = MyController;

'use strict';

// my-model.js exports the model
var MyModel = require('../models/my-model');

var MyController = {

       updateMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.swagger.params.id.value;  // Primary key
                myModel.attr2 = req.body.attr2;

                // Overwrites the object in the DB
                myModel.save(function(err, myModelUpdated) {
                        if (err) {
                            console.log("Error in update method");
                            res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelUpdated);
                });
       },

       postMyObject: function(req, res) {

                var myModel = new MyModel();

                myModel.attr1 = req.body.attr1; // primary key
                myModel.attr2 = req.body.attr2;

                myModel.save(function(err, myModelStored) {
                        if (err) {
                                console.log("Error in post method");
                                res.status(500).send({message: `${err}`});
                        }

                        res.status(200).send(myModelStored);
                });
       }
}

module.exports = MyController;

TypeError: myModel.save is not a function
    at updateMyObject (/home/user/my-server/api/controllers/my-controller.js:15:17)

如您所见，MyController的updateMyObject方法与postMyObject方法几乎相同，只是更新方法接收路径中的主键参数

为什么它抱怨model.save dynamoose API函数在updateMyObject方法中找不到，而它在postMyObject中工作正常

编辑： dynamoose模块在../models/my-model.js中导入：

var dynamoose = require('dynamoose');

---

刚刚编辑了我的问题，说明可以从控制器（my-model.js本身需要）访问dynamoose模块。您使用的是Express还是Hapi REST api？@conceptQuest我使用的是Express