Optimize Queries by Using Indexes

Overview

On this page, you can see copyable code examples that show how to manage different types of indexes by using the Kotlin Sync driver.

To use an example from this page, copy the code example into the sample application or your own application. Be sure to replace all placeholders in the code examples, such as <connection string URI>, with the relevant values for your MongoDB deployment.

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import com.mongodb.ConnectionString
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import com.mongodb.MongoClientSettings
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import com.mongodb.client.model.*
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import com.mongodb.kotlin.client.*
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import org.bson.Document
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fun main() {
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    val uri = "<connection string URI>"
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    val settings = MongoClientSettings.builder()
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        .applyConnectionString(ConnectionString(uri))
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        .retryWrites(true)
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        .build()
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    // Create a new client and connect to the server
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    val mongoClient = MongoClient.create(settings)
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    val database = mongoClient.getDatabase("<database name>")
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    val collection = database.getCollection<Document>("<collection name>")
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    // Start example code here
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    // End example code here
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}

Single Field Index

The following example creates an ascending index on the specified field:

collection.createIndex(Indexes.ascending("<field name>"))

To learn more about single field indexes, see the Single-Field Indexes guide.

Compound Index

The following example creates a compound index on the specified fields:

collection.createIndex(Indexes.ascending("<field name 1>", "<field name 2>"))

To learn more about compound indexes, see the Compound Indexes guide.

Multikey Index

The following example creates a multikey index on the specified array-valued field:

collection.createIndex(Indexes.ascending("<array field name>"))

Geospatial Index

The following example creates a 2dsphere index on the specified field that contains GeoJSON objects:

collection.createIndex(Indexes.geo2dsphere("<GeoJSON object field>"))

Unique Index

The following example creates a unique index on the specified field:

val indexOptions = IndexOptions().unique(true)
collection.createIndex(Indexes.ascending("<field name>"), indexOptions)

Wildcard Index

The following example creates a wildcard index in the specified collection:

collection.createIndex(Indexes.ascending("$**"))

Clustered Index

The following example creates a new collection with a clustered index on the _id field:

val clusteredIndexOptions = ClusteredIndexOptions(
    Indexes.ascending("_id"),
    true
)
val collection = database.createCollection("<collection name>", clusteredIndexOptions)

Atlas Search Index Management

The following sections contain code examples that describe how to manage Atlas Search indexes.

To learn more about Atlas Search indexes, see the Atlas Search and Vector Search Indexes guide.

val index = Document("mappings", Document("dynamic", true))
collection.createSearchIndex("<index name>", index)

val results = collection.listSearchIndexes()
results.forEach { result ->
    println(result)
}

val newIndex = Document("mappings", Document("dynamic", true))
collection.updateSearchIndex("<index name>", newIndex)

collection.dropIndex("<index name>")

Text Index

The following example creates a text index on the specified string field:

collection.createIndex(Indexes.text("<field name>"))

Delete an Index

The following example deletes an index with the specified name:

collection.dropIndex("<index name>")