Delete one record

Runs the sample. Generated for this page; it reads the connection string from the environment and first remakes the sample database from sample-schema.json.

using ArxSamples.DynamoDb;
using ArxSamples.DynamoDb.Operations.Delete.Basics;

// The connection string comes from the environment, never from the code (see "Configure the connection").
var connectionString = Environment.GetEnvironmentVariable("ARX_SAMPLES_DYNAMODB")
    ?? throw new InvalidOperationException("Set the ARX_SAMPLES_DYNAMODB environment variable to your Amazon DynamoDB connection string.");

var dbContext = new SampleContext(connectionString);

// Every run starts from the sample data: this deletes and makes again what sample-schema.json lists
// (save the file in the project folder, see Get started).
await dbContext.Direct.ResetAsync();

await new Basic1_DeleteOneRecord().RunAsync(dbContext);

The sample, as it is in the repository.

using ARX.SDK.DynamoDb.Services;
using ARX.SDK.Services;

using static ArxSamples.DynamoDb.SampleOutput;

namespace ArxSamples.DynamoDb.Operations.Delete.Basics;

/// <summary>
/// The smallest delete, in two scenarios: by the id Create returned, and an id no item has.
/// </summary>
/// <remarks>
/// <c>DeleteAsync(entityName, id)</c> returns true when an item went, false when none had the id: deleting twice
/// isn't an error. Several ids in one call are DeleteMultiple's.
/// </remarks>
public sealed class Basic1_DeleteOneRecord : ISample
{
    public string Name => "delete-basics-1-delete-one-record";

    public string Title => "Delete one record";

    public async Task RunAsync(SampleContext dbContext)
    {
        var product = new ArxEntity("product");
        product["sku"] = "SKU-D301";
        product["name"] = "Clearance item SKU-D301";
        var id = await dbContext.Service.CreateAsync(product);

        await Scenario1_ByTheIdCreateReturnedAsync(dbContext.Service, id);

        await Scenario2_AnIdNoItemHasAsync(dbContext.Service);
    }

    /// <summary>1. The id CreateAsync returned for SKU-D301.</summary>
    private static async Task Scenario1_ByTheIdCreateReturnedAsync(ArxDynamoDbService service, ArxRecordId id)
    {
        Step("1. By the id Create returned");

        bool deleted = await service.DeleteAsync("product", id);

        Show($"deleted: {deleted}");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT "sku" FROM "product" WHERE "sku" = 'SKU-D301'
         * -- Expect: no items.
         * ===========================================================
         */
    }

    /// <summary>2. SKU-D301 again: nothing to delete, so false, not an error.</summary>
    private static async Task Scenario2_AnIdNoItemHasAsync(ArxDynamoDbService service)
    {
        Step("2. An id no item has");

        bool deleted = await service.DeleteAsync("product", "SKU-D301");

        Show($"deleted: {deleted}");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT "sku" FROM "product" WHERE "sku" = 'SKU-D301'
         * -- Expect: no items.
         * ===========================================================
         */
    }
}

  > 1. By the id Create returned
      deleted: True
  > 2. An id no item has
      deleted: False