public override void Apply() { var providersIds = new List <string>(); var query = Database.FormatSql("SELECT \"Id\" FROM \"Providers\""); var reader = Database.ExecuteReader(query); while (reader.Read()) { providersIds.Add(reader[0].ToString()); } reader.Close(); foreach (var providerId in providersIds) { query = Database.FormatSql($"SELECT \"Id\" FROM \"ShippingWarehouses\" " + $"WHERE \"ProviderId\" = '{providerId}' AND \"WarehouseName\" = 'Коледино'"); reader = Database.ExecuteReader(query); if (!reader.Read()) { reader.Close(); AddShippingWarehouse(providerId); } else { reader.Close(); } } }