Working with items in DynamoDB

Dependencies

Include the following dependencies in your Package.swift file.

 dependencies: [
     .package(name: "AWSSwiftSDK",
              url: "https://github.com/awslabs/aws-sdk-swift",
              from: "0.1.0")
]

Add a target dependency to include the DynamoDB product within your Package.swift file. For example:

    targets: [
        .target(
            name: "<your target name>",
            dependencies: [.product(name: "AWSDynamoDB",
                                    package: "AWSSwiftSDK")]),
    ]

If needed, add appropriate platforms to your Package.swift file. For example, to declare support for macOS 10.15 and later as well as iOS 13 and later:

    platforms: [.macOS(.v10_15), .iOS(.v13)],

Imports

Add the following imports to your application source:

import AWSDynamoDB
import ClientRuntime
import AWSClientRuntime

Instantiate a service client

Before using DynamoDB, instantiate a service client object to handle requests:

let dynamoDbClient = try DynamoDbClient(region: "us-east-1")

Insert an item into a table

Use the putItem() method to insert a new record into a DynamoDB table. Refer to the following code snippet.

func putItemInTable(dynamoDbClient: DynamoDbClient,
                    nameOfTable: String,
                    key: String,
                    keyVal: String,
                    albumTitle: String,
                    titleOfAlbum: String,
                    awards: String,
                    awardVal: String,
                    songTitle: String,
                    titleOfSong: String
) {
    let itemValues = [ key : DynamoDbClientTypes.AttributeValue.s(keyVal),
                       songTitle: DynamoDbClientTypes.AttributeValue.s(titleOfSong),
                       albumTitle: DynamoDbClientTypes.AttributeValue.s(titleOfAlbum),
                       awards: DynamoDbClientTypes.AttributeValue.s(awardVal)]
    dynamoDbClient.putItem(input: PutItemInput(item: itemValues,
                tableName: nameOfTable)) { result in
        switch(result) {
        case .success:
            print("A new item was placed into \(nameOfTable)")
        case .failure(let err):
            print(err)
        }

    }
}

This example function defines a function that takes information about a song and writes it to a new record on DynamoDB.

Get an item from a table

Use the getItem() method to fetch an item from a DynamoDB table.

func getDynamoDbItem(dynamoDbClient: DynamoDbClient,
                     nameOfTable: String,
                     keyName: String,
                     keyVal: String) {
    let keyToGet = [keyName : DynamoDbClientTypes.AttributeValue.s(keyVal)]
    dynamoDbClient.getItem(input: GetItemInput(key: keyToGet, tableName: nameOfTable)) { result in
        switch(result) {
        case .success(let response):
            guard let numbersMap = response.item else {
                return
            }
            for returnedKey in numbersMap {
                print("\(returnedKey.key) : \(returnedKey.value)")
            }
        case .failure(let err):
            print(err)
        }
    }
}

Update an item in a table

Use the updateItem() method to update an item that’s already in a DynamoDB table.

func updateDynamoDbItem(dynamoDbClient: DynamoDbClient,
                        nameOfTable: String,
                        keyName: String,
                        keyVal: String,
                        name: String,
                        newValue: String
                       ) {
    let itemKey = [keyName : DynamoDbClientTypes.AttributeValue.s(keyVal)]
    let updatedValues = [name: DynamoDbClientTypes.AttributeValueUpdate(action: .put, value: DynamoDbClientTypes.AttributeValue.s(newValue))]
    dynamoDbClient.updateItem(input: UpdateItemInput(attributeUpdates: updatedValues, key: itemKey, tableName: nameOfTable)) { result in
        switch(result){
        case .success:
            print("Item in \(nameOfTable) was updated")
        case .failure(let err):
            print(err)
        }
    }
}

Delete an item from a table

To delete an item from a DynamoDB table, use the deleteItem() method, as shown in the following snippet.

func deleteDynamoDbItem(dynamoDbClient: DynamoDbClient,
                        nameOfTable: String,
                        keyName: String,
                        keyVal: String) {
    let keyToDelete = [keyName : DynamoDbClientTypes.AttributeValue.s(keyVal)]
    dynamoDbClient.deleteItem(input: DeleteItemInput(key: keyToDelete,
                        tableName: nameOfTable)) { result in
        switch(result) {
        case .success:
            print("Item with key matching \(keyVal) was deleted")
        case .failure(let err):
            print(err)
        }
    }
}

Additional information

• Guidelines for working with items in the Amazon DynamoDB Developer Guide

• Working with items in the Amazon DynamoDB Developer Guide