name: portada
class: portada-slide, center, middle

# Mongo Driver
### Persistència en mongoDB

.footnote[Mateu Yábar Valles]

---

# Mongo Atlas
Bases de dades MongoDB al núvol.

---
# Driver Mongo
- Driver offical Java
- POJOCodec - treball amb classes i no documents

---
# Gradle

```
implementation("org.mongodb:mongodb-driver-sync:4.7.1")
```

---
# Model

```
data class Item(
    var _id: ObjectId = ObjectId.get(),
    var complete: Boolean = false,
    var summary: String = "",
    var owner_id: String = "")
```

- Tot i no sér correcte en Kotlin deixarem els atributs _id i owner_id, per simplificar la configuració de Realm Sync

---
# Definir client
```
val pojoCodecProvider = PojoCodecProvider.builder().automatic(true).build()
val pojoCodecRegistry = fromRegistries(getDefaultCodecRegistry(), fromProviders(pojoCodecProvider))
val connectionString =
    ConnectionString("mongodb+srv://$user:$password@cluster0.ojxu5mw.mongodb.net/?retryWrites=true&w=majority")
val settings: MongoClientSettings = MongoClientSettings.builder()
    .applyConnectionString(connectionString)
    .serverApi(
        ServerApi.builder()
            .version(ServerApiVersion.V1)
            .build()
    )
    .build()
val mongoClient: MongoClient = MongoClients.create(settings)
```

---
# Col·lecció

```
val database: MongoDatabase = mongoClient.getDatabase("todo")
        .withCodecRegistry(pojoCodecRegistry);

val collection: MongoCollection<Item> = database.getCollection("Item", Item::class.java)
```

---
# Afegir

```
val item = Item(summary = "Something")
collection.insertOne(item)
```

---
# Llistar

```
val items = collection.find().toList()

val notCompleted = collection.find(Filters.eq("complete", false))
```

---
# Creació Mongo Atlas
- https://www.mongodb.com/cloud/atlas/register
- Crea shared cluster (free)
  - a Cloud Provider & Region, selecciona'n un proper

## Security Quickstart
- Crea un usuari i password per entrar
- Add entries to your IP Access List: Afegeix la ip actual
- Quan et surti "Introducing Termination Protection" fes skip

Ja tens una instancia de MongoDb al núvol.

T'hi pots connectar amb intellij ultimate usant la info a connect->Connect Using VS Code i copiant la info.

---
# Documentació

- https://www.mongodb.com/docs/drivers/java/sync/current/quick-start/
- https://learn.mongodb.com/learning-paths/mongodb-java-developer-path

---
# Altres
Per fer la suma de tots els elements, per cada un necessities fer un aggregate. Més info a :https://www.mongodb.com/docs/drivers/java/sync/current/fundamentals/aggregation/
Exemples:

```

// Sum of all the fileds named num
val sum = database.getCollection("LocationRealm").aggregate(
listOf(
Aggregates.group(null,
Accumulators.sum("total", "\$num"))
)
).single()["total"] as Int?

println(sum)

```

```
// Sum of fileds named grouped by category
val sumByCategoryResult = database.getCollection("LocationRealm").aggregate(
listOf(
Aggregates.group("\$category",
Accumulators.sum("sum", "\$num"))
)
)
sumByCategoryResult.forEach { println(it) }

val sumByCategoryAsMap = sumByCategoryResult.map{Pair(it["_id"], it["sum"] as Int?)}.toMap()

println(sumByCategoryAsMap)
```