Delete many records in one call

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.MongoDb;
using ArxSamples.MongoDb.Operations.DeleteMultiple.Basics;

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

The sample, as it is in the repository.

using ARX.SDK.MongoDb.Services;
using ARX.SDK.Services;

using static ArxSamples.MongoDb.SampleOutput;

namespace ArxSamples.MongoDb.Operations.DeleteMultiple.Basics;

/// <summary>
/// Many documents in one call, in two scenarios: by the ids Create returned, and by a list of entities found by the
/// declared key (the account number).
/// </summary>
/// <remarks>
/// By ids, ARX sends one <c>deleteMany</c> with <c>$in</c>. By entities, the deletes run in one transaction (a replica
/// set or a sharded cluster). Either way the call returns how many documents went: an id or a key no document has
/// isn't an error.
/// </remarks>
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 ids = new List<ArxRecordId>();

        foreach (var number in new[] { "ACC-M902", "ACC-M903", "ACC-M904", "ACC-M905" })
        {
            var account = new ArxEntity("account");
            account["name"] = "To delete " + number;
            account["account_number"] = number;
            ids.Add(await dbContext.Service.CreateAsync(account));
        }

        await Scenario1_ByIdsAsync(dbContext.Service, ids.Take(2).ToList());

        await Scenario2_ByTheDeclaredKeyAsync(dbContext.Service);
    }

    /// <summary>1. Two ids in one call.</summary>
    private static async Task Scenario1_ByIdsAsync(ArxMongoDbService service, IReadOnlyList<ArxRecordId> ids)
    {
        Step("1. By ids");

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

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

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * db.account.countDocuments({ account_number: { $in: ["ACC-M902", "ACC-M903"] } })
         * -- Expect: 0.
         * ===========================================================
         */
    }

    /// <summary>2. A list of account numbers, one of them unknown: the two found go.</summary>
    private static async Task Scenario2_ByTheDeclaredKeyAsync(ArxMongoDbService service)
    {
        Step("2. By the declared key");

        var requests = new[] { "ACC-M904", "ACC-M905", "ACC-M999" }.Select(number =>
        {
            var request = new ArxEntity("account");
            request["account_number"] = number;
            return request;
        }).ToList();

        int deleted = await service.DeleteMultipleAsync(requests, new ArxDeleteOptions { Match = ArxMatch.Key("account_number") });

        Show($"{deleted} of {requests.Count} documents deleted");

        /* ===========================================================
         * [DIRECT QUERY CHECK]
         * -----------------------------------------------------------
         * db.account.countDocuments({ account_number: { $in: ["ACC-M904", "ACC-M905"] } })
         * -- Expect: 0.
         * ===========================================================
         */
    }
}

  > 1. By ids
      2 documents deleted
  > 2. By the declared key
      2 of 3 documents deleted