# Databases

Node.js permet d'utiliser facilement toutes sortes de *databases* : SQL, NoSQL etc...

<https://github.com/felixge/node-mysql>

{% embed url="<https://github.com/felixge/node-mysql>" %}

<https://github.com/mongodb/node-mongodb-native>

{% embed url="<https://github.com/mongodb/node-mongodb-native>" %}

Pour la plupart des applications, il est préférable d'utiliser une base NoSQL telle que MongoDB pour bénéficier des avantages suivants :

* L'absence de schéma statique permet de s'adapter rapidement aux nouveaux besoins.
* La *scalability* grâce au *sharding*.
* Syntaxe simplifiée.
* Map/Reduce.
* ...

## ORM (Object-Relational Mapping) / ODM (Object-Document Mapping)

Comme dans les autres langages, il est fortement recommandé d'utiliser une couche d'abstraction pour des raisons de factorisation, simplification et sécurité.

### ORM SQL

<http://sequelizejs.com>

{% embed url="<http://sequelizejs.com>" %}

```javascript
const Sequelize = require('sequelize');
const sequelize = new Sequelize('database', 'username', 'password');

const User = sequelize.define('User', {
  firstName: Sequelize.STRING,
  lastName: Sequelize.STRING
});

const main = async () => {

    await sequelize.sync();
    
    const userModel = await User.create({firstName: 'Foo', lastName: 'BAR'});

    const user = user.get({plain: true})

};

main();
```

### ODM MongoDB

<http://mongoosejs.com/>

{% embed url="<http://mongoosejs.com/>" %}

```javascript
const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/test');

const User = mongoose.model('User', {
    firstName: String,
    lastName: String
});

const foo = new User({
    firstName: 'Foo',
    lastName: 'BAR'
});

await foo.save();
```


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