Getting Started With the MongoDB Kotlin Driver

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dependencies {
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    // Kotlin coroutine dependency
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    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4")
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    // MongoDB Kotlin driver dependency
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    implementation("org.mongodb:mongodb-driver-kotlin-coroutine:4.10.1")
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}

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val connectionString = "mongodb+srv://<username>:<enter your password>@cluster0.sq3aiau.mongodb.net/?retryWrites=true&w=majority"
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val client = MongoClient.create(connectionString = connectString)

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val databaseName = "sample_restaurants"
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val db: MongoDatabase = client.getDatabase(databaseName = databaseName)

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suspend fun setupConnection(
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    databaseName: String = "sample_restaurants",
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    connectionEnvVariable: String = "MONGODB_URI"
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): MongoDatabase? {
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    val connectString = if (System.getenv(connectionEnvVariable) != null) {
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        System.getenv(connectionEnvVariable)
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    } else {
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        "mongodb+srv://<usename>:<password>@cluster0.sq3aiau.mongodb.net/?retryWrites=true&w=majority"
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    }
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    val client = MongoClient.create(connectionString = connectString)
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    val database = client.getDatabase(databaseName = databaseName)
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    return try {
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        // Send a ping to confirm a successful connection
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        val command = Document("ping", BsonInt64(1))
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        database.runCommand(command)
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        println("Pinged your deployment. You successfully connected to MongoDB!")
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        database
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    } catch (me: MongoException) {
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        System.err.println(me)
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        null
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    }
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}

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suspend fun listAllCollection(database: MongoDatabase) {
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    val count = database.listCollectionNames().count()
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    println("Collection count $count")
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    print("Collection in this database are -----------> ")
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    database.listCollectionNames().collect { print(" $it") }
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}

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suspend fun dropCollection(database: MongoDatabase) {
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    database.getCollection<Objects>(collectionName = "restaurants").drop()
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}

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data class Restaurant(
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    @BsonId
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    val id: ObjectId,
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    val address: Address,
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    val borough: String,
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    val cuisine: String,
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    val grades: List<Grade>,
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    val name: String,
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    @BsonProperty("restaurant_id")
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    val restaurantId: String
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)
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data class Address(
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    val building: String,
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    val street: String,
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    val zipcode: String,
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    val coord: List<Double>
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)
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data class Grade(
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    val date: LocalDateTime,
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    val grade: String,
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    val score: Int
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)

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suspend fun addItem(database: MongoDatabase) {
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    val collection = database.getCollection<Restaurant>(collectionName = "restaurants")
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    val item = Restaurant(
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        id = ObjectId(),
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        address = Address(
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            building = "Building", street = "street", zipcode = "zipcode", coord =
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            listOf(Random.nextDouble(), Random.nextDouble())
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        ),
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        borough = "borough",
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        cuisine = "cuisine",
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        grades = listOf(
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            Grade(
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                date = LocalDateTime.now(),
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                grade = "A",
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                score = Random.nextInt()
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            )
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        ),
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        name = "name",
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        restaurantId = "restaurantId"
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    )
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    collection.insertOne(item).also {
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        println("Item added with id - ${it.insertedId}")
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    }
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}

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suspend fun addItems(database: MongoDatabase) {
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    val collection = database.getCollection<Restaurant>(collectionName = "restaurants")
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    val newRestaurants = collection.find<Restaurant>().first().run {
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        listOf(
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            this.copy(
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                id = ObjectId(), name = "Insert Many Restaurant first", restaurantId = Random
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                    .nextInt().toString()
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            ),
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            this.copy(
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                id = ObjectId(), name = "Insert Many Restaurant second", restaurantId = Random
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                    .nextInt().toString()
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            )
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        )
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    }
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    collection.insertMany(newRestaurants).also {
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        println("Total items added ${it.insertedIds.size}")
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    }
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}

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val collection = database.getCollection<Restaurant>(collectionName = "restaurants")
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collection.find<Restaurant>().limit(1).collect {
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    println(it)
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}

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val queryParams = Filters
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    .and(
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        listOf(
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            eq("cuisine", "American"),
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            eq("borough", "Queens")
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        )
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    )

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suspend fun readSpecificDocument(database: MongoDatabase) {
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    val collection = database.getCollection<Restaurant>(collectionName = "restaurants")
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    val queryParams = Filters
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        .and(
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            listOf(
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                eq("cuisine", "American"),
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                eq("borough", "Queens")
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            )
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        )
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    collection
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        .find<Restaurant>(queryParams)
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        .limit(2)
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        .collect {
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            println(it)
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        }
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}

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suspend fun readWithPaging(database: MongoDatabase, offset: Int, pageSize: Int) {
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    val collection = database.getCollection<Restaurant>(collectionName = "restaurants")
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    val queryParams = Filters
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        .and(
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            listOf(
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                eq(Restaurant::cuisine.name, "American"),
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                eq(Restaurant::borough.name, "Queens")
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            )
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        )
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    collection
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        .find<Restaurant>(queryParams)
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        .limit(pageSize)
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        .skip(offset)
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        .collect {
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            println(it)
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        }
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}

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val collection = database.getCollection<Restaurant>(collectionName = "restaurants")
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val options = IndexOptions().apply {
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    this.name("restaurant_id_index")
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    this.background(true)
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}
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collection.createIndex(
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    keys = Indexes.ascending("restaurant_id"),
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    options = options
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)

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val collection = db.getCollection<Restaurant>("restaurants")
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val queryParam = Filters.eq("restaurant_id", "restaurantId")

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val updateParams = Updates.set("restaurant_id", Random.nextInt().toString())

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collection.updateOne(filter = queryParam, update = updateParams).also {
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    println("Total docs modified ${it.matchedCount} and fields modified ${it.modifiedCount}")
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}

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suspend fun updateMultipleDocuments(db: MongoDatabase) {
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    val collection = db.getCollection<Restaurant>("restaurants")
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    val queryParam = Filters.eq(Restaurant::cuisine.name, "Chinese")
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    val updateParams = Updates.combine(
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        Updates.set(Restaurant::cuisine.name, "Indian"),
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        Updates.set(Restaurant::borough.name, "Brooklyn")
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    )
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    collection.updateMany(filter = queryParam, update = updateParams).also {
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        println("Total docs matched ${it.matchedCount} and modified ${it.modifiedCount}")
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    }
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}

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val collection = db.getCollection<Restaurant>(collectionName = "restaurants")
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val queryParams = Filters.eq("restaurant_id", "restaurantId")
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collection.findOneAndDelete(filter = queryParams).also {
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    it?.let {
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        println(it)
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    }
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}

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suspend fun deleteRestaurants(db: MongoDatabase) {
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    val collection = db.getCollection<Restaurant>(collectionName = "restaurants")
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    val queryParams = Filters.or(
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        listOf(
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            Filters.regex(Restaurant::name.name, Pattern.compile("^Insert")),
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            Filters.regex("restaurant_id", Pattern.compile("^restaurant"))
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        )
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    )
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    collection.deleteMany(filter = queryParams).also {
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        println("Document deleted : ${it.deletedCount}")
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    }
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}