Remove a contact by id or by email

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

using ArxSamples.MySQL;
using ArxSamples.MySQL.Operations.Delete.RealCases;

// 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 RealCase1_RemoveAContact().RunAsync(new SampleContext(connectionString));

The sample, as it is in the repository.

using ARX.SDK.Services;
using static ArxSamples.MySQL.SampleOutput;

namespace ArxSamples.MySQL.Operations.Delete.RealCases;

/// <summary>
/// Removing contacts, in two scenarios: from the contact screen (by id), and an "unsubscribe and forget me" request that
/// only gives the email address (the declared key).
/// </summary>
public sealed class RealCase1_RemoveAContact : ISample
{
    public string Name => "delete-real-1-remove-a-contact";

    public string Title => "Remove a contact by id or by email";

    public async Task RunAsync(SampleContext dbContext)
    {
        var first = new ArxEntity("contact");
        first["first_name"] = "Rosa";
        first["last_name"] = "Delgado";
        first["email"] = "rosa.delgado@example.com";

        var second = new ArxEntity("contact");
        second["first_name"] = "Omar";
        second["last_name"] = "Haddad";
        second["email"] = "omar.haddad@example.com";

        var ids = await dbContext.Service.CreateMultipleAsync(new List<ArxEntity> { first, second });

        await Scenario1_FromTheContactScreenAsync(dbContext, ids[0]);

        await Scenario2_ForgetMeByEmailAsync(dbContext);
    }

    /// <summary>1. The screen has the contact's id.</summary>
    private static async Task Scenario1_FromTheContactScreenAsync(SampleContext dbContext, ArxRecordId id)
    {
        Step("1. From the contact screen, by id");

        var deleted = await dbContext.Service.DeleteAsync("contact", id);
        Show($"deleted: {deleted}");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT count(*)
         * FROM contact
         * WHERE email = 'rosa.delgado@example.com';
         * -- Expect: 0.
         * ===========================================================
         */
    }

    /// <summary>2. A "forget me" request has only the email: delete by the key, strictly one row.</summary>
    private static async Task Scenario2_ForgetMeByEmailAsync(SampleContext dbContext)
    {
        Step("2. A forget-me request, by email");

        var request = new ArxEntity("contact");
        request["email"] = "omar.haddad@example.com";

        var deleted = await dbContext.Service.DeleteAsync(request, new ArxDeleteOptions { Match = ArxMatch.Key("email"), RequireSingleRow = true });
        Show($"{deleted} contact forgotten");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT count(*)
         * FROM contact
         * WHERE email = 'omar.haddad@example.com';
         * -- Expect: 0.
         * ===========================================================
         */
    }
}

  > 1. From the contact screen, by id
      deleted: True
  > 2. A forget-me request, by email
      1 contact forgotten