it must from req.body.user_id like this: user_id:req.body.user_id, They are used by Mongoose to … The lowercase option only works for strings. Setting _id: false option is handy because id’s are not needed on nested schemas because they’re just an abstraction to enable validation (required fields) and default values. Most apps will only use this one instance. Without it default score values will not be created on nested schemas. In this article, I am going to introduce you to Mongoose and MongoDB, and more importantly where these technologies fit in to your application. Mongoose is a JavaScript framework that is commonly used in a Node.js application with a MongoDB database. v.length is still required to be non-zero. A Mongoose schema defines the structure of the document, default values, validators, etc., whereas a Mongoose model provides an interface to the database for creating, querying, updating, deleting records, etc. We will use the following steps to use it: 1) On our backend, firstly, we need to add the schema for that. You are trying to get userId from req.user_id. A Mongoose model is a wrapper on the Mongoose schema. Mongoose comes with support for several built-in SchemaType options, like lowercase in the above example. Mongoose constructor. Setting the default for rating as empty object is crucial in order to enable creation of defaults. Your schemas can define default values for certain paths. Note: Mongoose only applies a default if … There are certain options which apply for all schema types, and some that apply for specific schema types. So, because you are interested to understand what i mean, let me try to do my best to explain the idea: there is two way to create a document with a other nested one: Now, we will use the Mongoose. @vkarpov15, thank you very much to not precipitate yourself to close a thread when you don't understand something and to care about what the users said, it is very nice.I appreciate. It is also possible to trigger it manually by calling the validate() method. We don't need to create a unique id on our own because the ID will be created automatically by Mongoose for us. I have an idea for a backward compatible solution: The checkRequired function will accept empty strings if the minlength is set to 0. I know Valeri was not so keen on this idea, so I will Mongoose registers validation as a pre ('save') hook on every schema by default. If you create a new document without that path set, the default will kick in. Referencing Mongoose Automattic , 6578 (comment) mongoose.set('required', true) to make all fields required: true by default. Mongoose: Set default value in a required field when this is not , 6578 (comment) mongoose.set('required', true) to make all fields required: true by default. Maps in Mongoose is a sub-class of the JavaScript's map class. To overwrite this default value, you need to provide a default value for the property: const schema = new Schema ({upvotes: {type: [Number], default: undefined}}); Maps. This can be seen as if the default value for minlength is 1, and the user need to set it to 0 if he wants to accept empty strings new mongoose.Schema({ name: { type: String, required: true } }) Validation logic is executed by Mongoose before a document can be saved to the database. We will go to our model.ts file, and this model shows us how a post looks like right now. Some of the Built-in validators include: Strings: minlength, maxlength, match, enum; Numbers: min, max; Dates: min, max The exports object of the mongoose module is an instance of this class. const m = new mongoose.Mongoose(); Example: const mongoose = require ('mongoose'); mongoose instanceof mongoose.Mongoose; // true // Create a new Mongoose instance with its own `connect()`, `set()`, `model()`, etc. Creating a Mongoose model comprises primarily of three parts: 1. All Schema Types.