AWS SDK で ListDatabases を使用する

    /// <summary>
    /// List databases in a Redshift cluster.
    /// </summary>
    /// <param name="clusterIdentifier">The cluster identifier.</param>
    /// <param name="dbUser">The database user.</param>
    /// <param name="dbUser">The database name for authentication.</param>
    /// <returns>A list of database names.</returns>
    public async Task<List<string>> ListDatabasesAsync(string clusterIdentifier, string dbUser, string databaseName)
    {
        try
        {
            var request = new ListDatabasesRequest
            {
                ClusterIdentifier = clusterIdentifier,
                DbUser = dbUser,
                Database = databaseName
            };

            var response = await _redshiftDataClient.ListDatabasesAsync(request);
            var databases = new List<string>();

            foreach (var database in response.Databases)
            {
                Console.WriteLine($"The database name is : {database}");
                databases.Add(database);
            }

            return databases;
        }
        catch (Amazon.RedshiftDataAPIService.Model.ValidationException ex)
        {
            Console.WriteLine($"Validation error: {ex.Message}");
            throw;
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Couldn't list databases. Here's why: {ex.Message}");
            throw;
        }
    }

    /**
     * Lists all databases asynchronously for the specified cluster, database user, and database.
     * @param clusterId the identifier of the cluster to list databases for
     * @param dbUser the database user to use for the list databases request
     * @param database the database to list databases for
     * @return a {@link CompletableFuture} that completes when the database listing is complete, or throws a {@link RuntimeException} if there was an error
     */
    public CompletableFuture<Void> listAllDatabasesAsync(String clusterId, String dbUser, String database) {
        ListDatabasesRequest databasesRequest = ListDatabasesRequest.builder()
            .clusterIdentifier(clusterId)
            .dbUser(dbUser)
            .database(database)
            .build();

        // Asynchronous paginator for listing databases.
        ListDatabasesPublisher databasesPaginator = getAsyncDataClient().listDatabasesPaginator(databasesRequest);
        CompletableFuture<Void> future = databasesPaginator.subscribe(response -> {
            response.databases().forEach(db -> {
                logger.info("The database name is {} ", db);
            });
        });

        // Return the future for asynchronous handling.
        return future.exceptionally(exception -> {
            throw new RuntimeException("Failed to list databases: " + exception.getMessage(), exception);
        });
    }