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Using Indexes

Scanamo supports scanning and querying global secondary indexes. In the following example, we create and use a table called transport with a hash key of mode and range key of line and a global secondary called colour-index with only a hash key on the colour attribute:

import org.scanamo._
import org.scanamo.syntax._

case class Transport(mode: String, line: String, colour: String)
val transport = Table[Transport]("transport")
val colourIndex = transport.index("colour-index")

val client = LocalDynamoDB.syncClient()
val scanamo = Scanamo(client)
LocalDynamoDB.withTableWithSecondaryIndex(client)("transport", "colour-index")("mode" -> S, "line" -> S)("colour" -> S) {
val operations = for {
_ <- transport.putAll(Set(
Transport("Underground", "Circle", "Yellow"),
Transport("Underground", "Metropolitan", "Maroon"),
Transport("Underground", "Central", "Red")))
maroonLine <- colourIndex.query("colour" === "Maroon")
} yield maroonLine.toList
// res0: List[Either[DynamoReadError, Transport]] = List(
// Right(Transport("Underground", "Metropolitan", "Maroon"))
// )