使用 monogoose 将对象推送到节点 js 中的数组属性时出现错误

Posted 2023-02-16

【中文标题】使用 monogoose 将对象推送到节点 js 中的数组属性时出现错误

【英文标题】：I am getting an error while i am pushing an object to the array property in node js using monogoose

【发布时间】：2022-01-07 05:49:40

【问题描述】：

My Problem is i want after i create the categoryName and then i create the product properties, then i can push the product properties to the categoryProduct field.

我尝试使用 $push 并在数据库中给了我一个空数组。

CallBack Function for creating a product

//Here i am getting the values from the body

//create an object 

const productObject = new productSchema(

    productName: req.body.productName,
    productPrice: req.body.productPrice,
    productCategory: req.body.productCategory,
    productQuantity: req.body.productQuantity,
    productSection: req.body.productSection,
    productExDate: req.body.productExDate

)


    //saving 
    productObject
        .save()
        .then(data => 
            res.redirect('/halalMunchies/all-products');
        )
        .catch(err => 
            res.status(500).send(
                message: err.message || "Some error occured while creating a create operation"
            );
        );

    //pushing inside the productCategory in the category model

    categoryDB.findOneAndUpdate( categoryName: req.body.productCategory ,  $push:  productsCategory: productObject._id  )
        .then(result => 
            console.log(result);
        )
        .catch(err => 
            console.log(err);
        )

the output

  
  _id: new ObjectId("61a62e619c17c622153c4d1a"),
  categoryName: 'meat',
  productsCategory: [],
  __v: 0

在categoryschema 中我有categoryname 和productsCategory 包含该类别拥有的所有产品。 Category Schema

    var categorySchema = new mongoose.Schema(

    //properties // shape of the documentation

    categoryName: 
        type: String,
        required: true,
        unique: true

    ,

    productsCategory: [
        type: mongoose.Schema.Types.ObjectId,
        ref: 'productSchema',
        required: true
    ]

);

const categoryDB = mongoose.model('categorySchema', categorySchema);

在productSchema 中，它的一个属性是productCategory，它引用categorySchema

    var productSchema = new mongoose.Schema(

    //defining the properties

    productName: 
        type: String,
        unique: true,
        required: [true, 'Product name is required'] // we can pass a message like this 
    ,

    productCategory: 
        type: mongoose.Schema.Types.String,
        ref: 'categorySchema',
        required: [true, 'Category name is required'] // we can pass a message like this 
    ,

    productPrice: 
        type: Float,
        required: [true, 'Price name is required'] // we can pass a message like this 
    ,

    productQuantity: 
        type: Number,
        required: [true, 'Quantity name is required'] // we can pass a message like this 
    ,

    productSection: 
        type: String,
        required: [true, 'Section name is required'] // we can pass a message like this 
    ,

    productExDate: 
        type: String,
        required: [true, 'ExDate name is required'] // we can pass a message like this 
    


)

const productDB = mongoose.model('productSchema', productSchema);

【参考方案1】：

你可以这样尝试，假设我们为了简单起见使用异步函数来避免 .then .catch 痛苦的过程：

const 
  productData,
  productCategory,
 = req.body;

const productObject = new productSchema( ...productData );

await productObject.save();

const categoryObject = await categorySchema.findOne( categoryName: productCategory );

if (!categoryObject) 
  // Throw some error


await categoryObject.productsCategory.push(productObject._id);
await categoryObject.save();

// then make your redirect to /halalMunchies/all-products

---

编辑

const 
  productName,
  productPrice,
  productQuantity,
  productSection,
  productExDate,
  productCategory,
 = req.body;

const productObject = new productSchema(
  productName,
  productPrice,
  productCategory,
  productQuantity,
  productSection,
  productExDate,
);

await productObject.save();

如果您的意思是 productCategory "category id"，那么您应该通过 _id 获取：

const categoryObject = await categorySchema.findOne( _id: productCategory );

if (!categoryObject) 
  // Throw some error


await categoryObject.productsCategory.push(productObject._id);
await categoryObject.save();

// then make your redirect to /halalMunchies/all-products

【讨论】：

categorySchema.findOne( categoryName: productCategory ); 这行应该只返回用户输入的categoryName，并且你设置它等于categoryObject，所以这个对象只有一个属性。在这个await categoryObject.productsCategory.push(productObject._id); productsCategory 中未定义。

根据您在上面定义的 categorySchema，productsCategory 不能是未定义的，我提供的代码所做的就是它获取 categoryName 等于 productCategory 的类别，如果有这样的文档，它将通过推送新创建的 productObject 的 id 来更新 productsCategory 属性字段。如果 productsCategory 未定义，正如您所说的那样，首先创建类别文档时出现问题。

你能再看一下吗，我更新了创建对象以获取正文值的方式，我该如何基于此进行。谢谢你的帮助

感谢人的帮助