Databases

Mongoose

About

• Mongoose .

• It's a wrapper for MongoDB.

  • Database - Document Oriented .

• Is Mongoose an ORM?

  • Mongoose is not technically an ORM (Object-Relational Mapping), but rather an ODM (Object-Document Mapping).

  • Although both ORM and ODM have similar goals — mapping objects in code to database entities — the difference is the type of database each one handles.

Explanations

• Tutorial, with schema construction and queries .

• HTTP Server with CRUD API and Mongoose database .

  • The presenter uses Mongoose Atlas, but it should not make a difference.

  • The video is of poor quality and poorly explained, but if you have some background before watching it, it is possible to watch it without quitting.

  • Repository with all the code .

  • {33:47}:

    • Schema and Model created.

    • Connection established with the Mongoose server.

  • {49:10}:

    • Create a GET that receives an ID in the URL as a parameter.

  • {58:37}:

    • Update a product based on the ID, with PUT.

Database

• How to rename a Database .

  • I don't really know yet where the DB lives on the filesystem.

    • There are files inside Program Files/mongodb .

Schemas and Models

• Creating a Schema and Model:

import mongoose from 'npm:mongoose';

mongoose.connect('mongodb://localhost/meu_banco', { useNewUrlParser: true, useUnifiedTopology: true });

const user_schema = new mongoose.Schema({
  nome: { type: String, required: true },
  email: { type: String, required: true, unique: true },
  idade: { type: Number, min: 18 }
});

const User = mongoose.model('User', user_schema);

• Collection name:

  • .

Documents

• Via new Model  and .save

const new_user = new User({
  nome: 'John',
  email: 'john@email.com',
  idade: 25
});

new_user.save()
  .then(() => console.log('User saved!'))
  .catch((err) => console.log('Error saving the user:', err));

• Via .create :

const new_character = await Character.create({
    nome: 'John',
});

Validations

• Taken from the video above .

• A schema created by default has its properties set as 'not required'.

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