Delete many records in one call

Runs the sample. Generated for this page; it reads the connection string from the environment.

using ArxSamples.MySQL;
using ArxSamples.MySQL.Operations.DeleteMultiple.Basics;

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

await new Basic1_DeleteManyRecords().RunAsync(new SampleContext(connectionString));

The sample, as it is in the repository.

using ARX.SDK.MySQL.Services;
using ARX.SDK.Services;

using static ArxSamples.MySQL.SampleOutput;

namespace ArxSamples.MySQL.Operations.DeleteMultiple.Basics;

/// <summary>
/// Many records in one call, in two scenarios: by the ids CreateMultiple returned; and a list with an id that doesn't
/// exist and one given twice, both counted honestly.
/// </summary>
public sealed class Basic1_DeleteManyRecords : ISample
{
    public string Name => "delete-multiple-basics-1-delete-many-records";

    public string Title => "Delete many records in one call";

    public async Task RunAsync(SampleContext dbContext)
    {
        var service = new ArxMySqlDbService(dbContext.ConnectionString, ArxSchemaCatalog.Create()
            .Table("account", ArxIdColumn.Generated<long>("id"))
            .Build());

        await Scenario1_ByTheIdsCreateReturnedAsync(service);

        await Scenario2_MissingAndRepeatedIdsAsync(service);
    }

    private static async Task<IReadOnlyList<ArxRecordId>> CreateAccountsAsync(ArxMySqlDbService service, int first, int count)
    {
        var accounts = Enumerable.Range(first, count).Select(i =>
        {
            var account = new ArxEntity("account");
            account["name"] = $"Delete many {i}";
            account["account_number"] = $"ACC-D2{i:00}";
            return account;
        }).ToList();

        return await service.CreateMultipleAsync(accounts);
    }

    /// <summary>1. The usual way: the table and the ids. The call returns how many records went.</summary>
    private static async Task Scenario1_ByTheIdsCreateReturnedAsync(ArxMySqlDbService service)
    {
        Step("1. By the ids Create returned");

        var ids = await CreateAccountsAsync(service, 1, 5);

        int deleted = await service.DeleteMultipleAsync("account", ids);

        Show($"{deleted} deleted");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT count(*)
         * FROM account
         * WHERE account_number BETWEEN 'ACC-D201' AND 'ACC-D205';
         * -- Expect: 0.
         * ===========================================================
         */
    }

    /// <summary>2. A missing id isn't an error, and an id given twice goes once: the count says what really happened.</summary>
    private static async Task Scenario2_MissingAndRepeatedIdsAsync(ArxMySqlDbService service)
    {
        Step("2. Missing and repeated ids");

        var ids = (await CreateAccountsAsync(service, 11, 3)).Select(x => x.AsInt64()).ToList();
        var list = new List<long> { ids[0], ids[1], ids[2], ids[0], 999_999_995 };

        int deleted = await service.DeleteMultipleAsync("account", list);

        Show($"asked for {list.Count}, {deleted} deleted");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT count(*)
         * FROM account
         * WHERE account_number BETWEEN 'ACC-D211' AND 'ACC-D213';
         * -- Expect: 0.
         * ===========================================================
         */
    }
}

What every sample is given: the connection string (and the ISample interface the samples implement).

namespace ArxSamples.MySQL;

/// <summary>One documentation sample: a scenario a real application has, shown end to end.</summary>
public interface ISample
{
    /// <summary>The name to run it alone: <c>dotnet run -- &lt;name&gt;</c>.</summary>
    string Name { get; }

    /// <summary>One line on what it shows.</summary>
    string Title { get; }

    Task RunAsync(SampleContext dbContext);
}

/// <summary>
/// What a sample is given. Every sample gets the connection string; the application's service and catalog
/// (SampleContext.Application.cs) and the plain MySqlConnector read-back helper (SampleContext.Direct.cs) live in their own
/// files, so a sample needs only the files it uses.
/// </summary>
public sealed partial class SampleContext
{
    public SampleContext(string connectionString)
    {
        ConnectionString = connectionString;
    }

    public string ConnectionString { get; }
}

How the samples print: Step for each scenario, Show for what it did, ShowError for an error caught on purpose.

using ARX.SDK;

namespace ArxSamples.MySQL;

/// <summary>How the samples print: a numbered step for each scenario, then what it did.</summary>
public static class SampleOutput
{
    /// <summary>The start of a scenario: <c>Step("1. By the id Create returned")</c>.</summary>
    public static void Step(string text) => Console.WriteLine($"  > {text}");

    /// <summary>What the scenario did.</summary>
    public static void Show(string text) => Console.WriteLine($"      {text}");

    /// <summary>An ARX error the scenario caught on purpose.</summary>
    public static void ShowError(ArxException exception)
        => Console.WriteLine($"      caught {exception.GetType().Name}: {exception.Message}");
}

  > 1. By the ids Create returned
      5 deleted
  > 2. Missing and repeated ids
      asked for 5, 3 deleted