Ids that aren't numbers: text and uuid

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

using ArxSamples.PostgreSql;
using ArxSamples.PostgreSql.Operations.Create.Basics;

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

await new Basic4_TextAndUuidIds().RunAsync(new SampleContext(connectionString));

The sample, as it is in the repository.

using ARX.SDK.PostgreSql.Services;
using ARX.SDK.Services;

using static ArxSamples.PostgreSql.SampleOutput;

namespace ArxSamples.PostgreSql.Operations.Create.Basics;

/// <summary>
/// Ids that aren't numbers, in three scenarios: a text id you supply (a country code), a uuid the database generates,
/// and a uuid your code generates.
/// </summary>
public sealed class Basic4_TextAndUuidIds : ISample
{
    public string Name => "create-basics-4-text-and-uuid-ids";

    public string Title => "Ids that aren't numbers: text and uuid";

    public async Task RunAsync(SampleContext dbContext)
    {
        await Scenario1_ATextIdYouSupplyAsync(dbContext.ConnectionString);

        await Scenario2_AUuidTheDatabaseGeneratesAsync(dbContext.ConnectionString);

        await Scenario3_AUuidYourCodeGeneratesAsync(dbContext.ConnectionString);
    }

    /// <summary>1. A text id you supply: the country code. Supplied means you always set it.</summary>
    private static async Task Scenario1_ATextIdYouSupplyAsync(string connectionString)
    {
        Step("1. Text id you supply");

        var schema = ArxSchemaCatalog.Create()
            .Table("country", ArxIdColumn.Supplied<string>("code"))
            .Build();

        var service = new ArxPgDbService(connectionString, schema);

        var country = new ArxEntity("country");
        country["code"] = "PT";
        country["name"] = "Portugal";

        ArxRecordId id = await service.CreateAsync(country);

        // A text id is read with AsString().
        Show($"created country {id.AsString()}");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT code, name
         * FROM country
         * WHERE code = 'PT';
         * -- Expect: 1 row, Portugal.
         * ===========================================================
         */
    }

    /// <summary>2. A uuid the database generates (DEFAULT gen_random_uuid()): leave the id out.</summary>
    private static async Task Scenario2_AUuidTheDatabaseGeneratesAsync(string connectionString)
    {
        Step("2. Uuid the database makes");

        var schema = ArxSchemaCatalog.Create()
            .Table("device", ArxIdColumn.Generated<Guid>("id"))
            .Build();

        var service = new ArxPgDbService(connectionString, schema);

        var device = new ArxEntity("device");
        device["serial_number"] = "DEV-0001";

        ArxRecordId id = await service.CreateAsync(device);

        // A uuid is read with AsGuid().
        Show($"created device {id.AsGuid()}");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT id, serial_number
         * FROM device
         * WHERE serial_number = 'DEV-0001';
         * -- Expect: 1 row, with the uuid the database generated.
         * ===========================================================
         */
    }

    /// <summary>3. A uuid your code generates: set the id, and it's written as given.</summary>
    private static async Task Scenario3_AUuidYourCodeGeneratesAsync(string connectionString)
    {
        Step("3. Uuid your code makes");

        // The same declaration as scenario 2: Generated means the database CAN fill it in, not that it must.
        var schema = ArxSchemaCatalog.Create()
            .Table("device", ArxIdColumn.Generated<Guid>("id"))
            .Build();

        var service = new ArxPgDbService(connectionString, schema);

        var myId = Guid.NewGuid();

        var device = new ArxEntity("device");
        device["id"] = myId;
        device["serial_number"] = "DEV-0002";

        ArxRecordId id = await service.CreateAsync(device);

        Show($"created device {id.AsGuid()} (the same as myId: {id.AsGuid() == myId})");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * SELECT id, serial_number
         * FROM device
         * WHERE serial_number = 'DEV-0002';
         * -- Expect: 1 row, with the uuid the sample printed (myId).
         * ===========================================================
         */
    }
}

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

namespace ArxSamples.PostgreSql;

/// <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 Npgsql 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.PostgreSql;

/// <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. Text id you supply
      created country PT
  > 2. Uuid the database makes
      created device c46b1e09-d75d-4360-bfe0-57e705c22bf9
  > 3. Uuid your code makes
      created device c1382b33-3f39-4272-b4c2-cf2ac796beaf (the same as myId: True)