mongoose-CRUD-using-node-repl.md

Perform CRUD Using Mongoose Models in a Node REPL

1. Start by opening a terminal session and make sure that you are in the project's root folder.

2. Start a Node REPL:

   $ node
   > 

3. Connect to the MongoDB database:

   // If the db connection string is in a .env file, we need to process it just like in server.js
   > require('dotenv').config()
   // Connect to the database
   > require('./config/database')
   {}
   > Connected to MongoDB at localhost:27017
   // Press enter to return to the prompt

4. Load the Models, for example, Movie:

   > const Movie = require('./models/movie')

5. Curious what the Movie Model looks like?

   > Movie
   // a big object...

   Important: If you make any changes to a Model, you'll have exit Node and start again.

6. Log all movie docs:

   > Movie.find({}, (e, movies) => {
   ... console.log(movies)
   ... })

   The find method returns a Query object that is first logged, followed by the movie docs. Press enter to return to the prompt.

7. Anything that can be done with a Model in an Express app, can be done in the REPL including CRUD operations, manipulate individual documents, etc.

8. Here's a way to delete all documents from a collection:

   > Movie.deleteMany({}, (err, result) => console.log(result))
   ...
   > { n: 3, ok: 1, deletedCount: 3 }

   The empty query object provided as the first argument matches all documents, so all documents were removed.

9. And here's a way to update all documents in a collection:

   // reset all cast arrays to be empty
   > Movie.updateMany({}, {cast: []}, (err, result) => console.log(result))
   ...
   > { n: 3, nModified: 3, ok: 1 }

   The second object has the properties with their new values that you want to update.

10. Press control + C twice to exit the REPL.