http methods express mongoose schema model request handler post method postman timestamp find() validations CRUD operations server findById params runValidators new: true api callback functions collection document field populate port connect save database then() catch() promise obj required json stingify app.use() middleware express.json() npm schema cors model package.json request obj response obj 27017 uri findByIdAndDelete findByIdAndUpdate localhost null 404 status codes req.body app.listen() Schema.Types.ObjectId ODM ORM port require() constructor function Async static method instance method express - validator ref min req.params.id :id in the url deleteMany() isNew type error object app.get() app.post() app.put() app.delete() header Access-Control-Allow-Origin npm init package.json dependecies node_modules REST API response.json() createdAt, updatedAt - timestamps package.lock.json primary key - foreign key cli gui new Category() npm install nodemon postman body methods compass singular plural naming conventions 127.0.0.1 select options mongodb:// db - strictly type UTC