feat: 完成后端API路由、交易服务和数据库模式的初始搭建

database/sql/schema.sql

@@ -167,6 +167,13 @@ CREATE TABLE IF NOT EXISTS `transaction_tags` (
   CONSTRAINT `fk_transaction_tags_transaction` FOREIGN KEY (`transaction_id`) REFERENCES `transactions` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 
+-- Account Tags table (Many-to-Many)
+CREATE TABLE IF NOT EXISTS `account_tags` (
+  `account_id` bigint(20) unsigned NOT NULL,
+  `tag_id` bigint(20) unsigned NOT NULL,
+  PRIMARY KEY (`account_id`,`tag_id`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
 -- Transaction Images table
 CREATE TABLE IF NOT EXISTS `transaction_images` (
   `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
@@ -553,6 +560,7 @@ CREATE TABLE IF NOT EXISTS `user_settings` (
   CONSTRAINT `fk_user_settings_default_expense` FOREIGN KEY (`default_expense_account_id`) REFERENCES `accounts` (`id`) ON DELETE SET NULL ON UPDATE CASCADE,
   CONSTRAINT `fk_user_settings_default_income` FOREIGN KEY (`default_income_account_id`) REFERENCES `accounts` (`id`) ON DELETE SET NULL ON UPDATE CASCADE
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
 -- Notifications table
 CREATE TABLE IF NOT EXISTS `notifications` (
   `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,