diff --git a/Makefile b/Makefile
index 17c26dc..04da5e8 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,7 @@
 	backend-build backend-run backend-dev backend-test backend-test-unit backend-test-integration backend-test-coverage \
 	backend-lint backend-clean backend-deps backend-generate \
 	backend-db-up backend-db-down backend-db-status backend-db-create \
+	test-mysql-up test-mysql-down test-mysql test-mysql-quick \
 	frontend-build frontend-dev frontend-test frontend-test-watch frontend-test-coverage frontend-test-e2e frontend-lint frontend-clean \
 	desktop-build desktop-build-mac desktop-build-win desktop-build-linux \
 	desktop-dev desktop-package-mac desktop-package-win desktop-package-linux desktop-clean \
@@ -66,17 +67,53 @@ backend-generate:
 	cd backend && go generate ./...
 
 backend-db-up:
-	cd backend && goose -dir migrations sqlite3 $(DB_PATH) up
+	@echo "Running database migration up..."
+	cd backend && goose -dir migrations/sqlite3 sqlite3 "$(DB_PATH)" up
 
 backend-db-down:
-	cd backend && goose -dir migrations sqlite3 $(DB_PATH) down
+	@echo "Running database migration down..."
+	cd backend && goose -dir migrations/sqlite3 sqlite3 "$(DB_PATH)" down
 
 backend-db-status:
-	cd backend && goose -dir migrations sqlite3 $(DB_PATH) status
+	@echo "Checking database migration status..."
+	cd backend && goose -dir migrations/sqlite3 sqlite3 "$(DB_PATH)" status
 
 backend-db-create:
 	@read -p "Migration name: " name; \
-	cd backend && goose -dir migrations create $$name sql
+	cd backend && goose -dir migrations/sqlite create $$name sql; \
+	cd backend && goose -dir migrations/mysql create $$name sql
+
+# ============================================
+# MySQL 专项测试
+# ============================================
+
+test-mysql-up:
+	@echo "Starting MySQL test container..."
+	cd backend/tests/mysql && docker-compose up -d
+	@echo "Waiting for MySQL to be ready..."
+	@for i in $$(seq 1 30); do \
+		if docker exec nex-mysql-test mysqladmin ping -h localhost -u root -ptestpass --silent 2>/dev/null; then \
+			echo "MySQL is ready!"; \
+			exit 0; \
+		fi; \
+		echo "Waiting... ($$i/30)"; \
+		sleep 1; \
+	done; \
+	echo "MySQL failed to start"; \
+	exit 1
+
+test-mysql-down:
+	@echo "Stopping MySQL test container..."
+	cd backend/tests/mysql && docker-compose down -v
+
+test-mysql: test-mysql-up
+	@echo "Running MySQL tests..."
+	cd backend && go test -tags=mysql ./tests/mysql/... -v -count=1
+	$(MAKE) test-mysql-down
+
+test-mysql-quick:
+	@echo "Running MySQL tests (without container management)..."
+	cd backend && go test -tags=mysql ./tests/mysql/... -v -count=1
 
 # ============================================
 # 前端
diff --git a/README.md b/README.md
index 64793cb..09b18bb 100644
--- a/README.md
+++ b/README.md
@@ -66,7 +66,7 @@ nex/
 - **语言**: Go 1.26+
 - **HTTP 框架**: Gin
 - **ORM**: GORM
-- **数据库**: SQLite
+- **数据库**: SQLite / MySQL
 - **日志**: zap + lumberjack（结构化日志 + 日志轮转）
 - **配置**: Viper + pflag（多层配置：CLI > 环境变量 > 配置文件 > 默认值）
 - **验证**: go-playground/validator/v10
@@ -204,7 +204,14 @@ server:
   write_timeout: 30s
 
 database:
-  path: ~/.nex/config.db
+  driver: sqlite               # sqlite 或 mysql
+  path: ~/.nex/config.db       # SQLite 数据库文件路径
+  # --- MySQL 配置（driver=mysql 时生效）---
+  # host: localhost
+  # port: 3306
+  # user: nex
+  # password: ""
+  # dbname: nex
   max_idle_conns: 10
   max_open_conns: 100
   conn_max_lifetime: 1h
@@ -226,6 +233,14 @@ log:
 export NEX_SERVER_PORT=9000
 export NEX_DATABASE_PATH=/data/nex.db
 export NEX_LOG_LEVEL=debug
+
+# MySQL 模式
+export NEX_DATABASE_DRIVER=mysql
+export NEX_DATABASE_HOST=db.example.com
+export NEX_DATABASE_PORT=3306
+export NEX_DATABASE_USER=nex
+export NEX_DATABASE_PASSWORD=secret
+export NEX_DATABASE_DBNAME=nex
 ```
 
 命名规则：配置路径转大写 + 下划线（如 `server.port` → `NEX_SERVER_PORT`）。
@@ -241,7 +256,7 @@ export NEX_LOG_LEVEL=debug
 ### 数据文件
 
 - `~/.nex/config.yaml` - 配置文件
-- `~/.nex/config.db` - SQLite 数据库
+- `~/.nex/config.db` - SQLite 数据库（MySQL 模式下不使用本地数据库文件）
 - `~/.nex/log/` - 日志目录
 
 ## 测试
diff --git a/backend/README.md b/backend/README.md
index 4041b3e..fc7f136 100644
--- a/backend/README.md
+++ b/backend/README.md
@@ -24,7 +24,7 @@ AI 网关后端服务，提供统一的大模型 API 代理接口。
 - **语言**: Go 1.26+
 - **HTTP 框架**: Gin
 - **ORM**: GORM
-- **数据库**: SQLite
+- **数据库**: SQLite / MySQL
 - **日志**: zap + lumberjack
 - **配置**: Viper + pflag（多层配置：CLI > 环境变量 > 配置文件 > 默认值）
 - **验证**: go-playground/validator/v10
@@ -294,7 +294,14 @@ server:
   write_timeout: 30s
 
 database:
-  path: ~/.nex/config.db
+  driver: sqlite               # sqlite 或 mysql
+  path: ~/.nex/config.db       # SQLite 数据库文件路径
+  # --- MySQL 配置（driver=mysql 时生效）---
+  # host: localhost
+  # port: 3306
+  # user: nex
+  # password: ""
+  # dbname: nex
   max_idle_conns: 10
   max_open_conns: 100
   conn_max_lifetime: 1h
@@ -316,6 +323,14 @@ log:
 export NEX_SERVER_PORT=9000
 export NEX_DATABASE_PATH=/data/nex.db
 export NEX_LOG_LEVEL=debug
+
+# MySQL 模式
+export NEX_DATABASE_DRIVER=mysql
+export NEX_DATABASE_HOST=db.example.com
+export NEX_DATABASE_PORT=3306
+export NEX_DATABASE_USER=nex
+export NEX_DATABASE_PASSWORD=secret
+export NEX_DATABASE_DBNAME=nex
 ```
 
 命名规则：配置路径转大写 + 下划线 + `NEX_` 前缀（如 `server.port` → `NEX_SERVER_PORT`）。
@@ -332,7 +347,7 @@ export NEX_LOG_LEVEL=debug
 
 ```
 服务器:   --server-port, --server-read-timeout, --server-write-timeout
-数据库:   --database-path, --database-max-idle-conns, --database-max-open-conns, --database-conn-max-lifetime
+数据库:   --database-driver, --database-path, --database-host, --database-port, --database-user, --database-password, --database-dbname, --database-max-idle-conns, --database-max-open-conns, --database-conn-max-lifetime
 日志:     --log-level, --log-path, --log-max-size, --log-max-backups, --log-max-age, --log-compress
 通用:     --config (指定配置文件路径)
 ```
@@ -352,15 +367,20 @@ export NEX_LOG_LEVEL=debug
 # Docker 部署
 docker run -d -e NEX_SERVER_PORT=9000 -e NEX_LOG_LEVEL=info nex-server
 
+# MySQL 模式
+./server --database-driver mysql --database-host db.example.com --database-user nex --database-password secret --database-dbname nex
+
 # 自定义配置文件
 ./server --config /path/to/custom.yaml
 ```
 
 数据文件：
 - `~/.nex/config.yaml` - 配置文件
-- `~/.nex/config.db` - SQLite 数据库
+- `~/.nex/config.db` - SQLite 数据库（MySQL 模式下不使用本地数据库文件）
 - `~/.nex/log/` - 日志目录
 
+**MySQL 连接说明**：MySQL 连接使用 DSN 格式: `user:password@tcp(host:port)/dbname?charset=utf8mb4&parseTime=true&loc=Local`，最低支持 MySQL 8.0+。
+
 ## 测试
 
 ```bash
diff --git a/backend/cmd/desktop/main.go b/backend/cmd/desktop/main.go
index f43832d..aabd816 100644
--- a/backend/cmd/desktop/main.go
+++ b/backend/cmd/desktop/main.go
@@ -17,16 +17,13 @@ import (
 	"github.com/getlantern/systray"
 	"github.com/gin-gonic/gin"
 	"github.com/gofrs/flock"
-	"github.com/pressly/goose/v3"
 	"go.uber.org/zap"
-	"gorm.io/driver/sqlite"
-	"gorm.io/gorm"
-	"gorm.io/gorm/logger"
 
 	"nex/backend/internal/config"
 	"nex/backend/internal/conversion"
 	"nex/backend/internal/conversion/anthropic"
 	"nex/backend/internal/conversion/openai"
+	"nex/backend/internal/database"
 	"nex/backend/internal/handler"
 	"nex/backend/internal/handler/middleware"
 	"nex/backend/internal/provider"
@@ -79,12 +76,12 @@ func main() {
 	}
 	defer zapLogger.Sync()
 
-	db, err := initDatabase(cfg)
+	db, err := database.Init(&cfg.Database, zapLogger)
 	if err != nil {
 		showError("Nex Gateway", fmt.Sprintf("初始化数据库失败: %v", err))
 		os.Exit(1)
 	}
-	defer closeDB(db)
+	defer database.Close(db)
 
 	providerRepo := repository.NewProviderRepository(db)
 	modelRepo := repository.NewModelRepository(db)
@@ -159,76 +156,6 @@ func main() {
 	setupSystray(port)
 }
 
-func initDatabase(cfg *config.Config) (*gorm.DB, error) {
-	dbDir := filepath.Dir(cfg.Database.Path)
-	if err := os.MkdirAll(dbDir, 0755); err != nil {
-		return nil, fmt.Errorf("创建数据库目录失败: %w", err)
-	}
-
-	db, err := gorm.Open(sqlite.Open(cfg.Database.Path), &gorm.Config{
-		Logger: logger.Default.LogMode(logger.Info),
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	if err := runMigrations(db); err != nil {
-		return nil, fmt.Errorf("数据库迁移失败: %w", err)
-	}
-
-	if err := db.Exec("PRAGMA journal_mode=WAL").Error; err != nil {
-		log.Printf("警告: 启用 WAL 模式失败: %v", err)
-	}
-
-	sqlDB, err := db.DB()
-	if err != nil {
-		return nil, err
-	}
-	sqlDB.SetMaxIdleConns(cfg.Database.MaxIdleConns)
-	sqlDB.SetMaxOpenConns(cfg.Database.MaxOpenConns)
-	sqlDB.SetConnMaxLifetime(cfg.Database.ConnMaxLifetime)
-
-	return db, nil
-}
-
-func runMigrations(db *gorm.DB) error {
-	sqlDB, err := db.DB()
-	if err != nil {
-		return err
-	}
-
-	migrationsDir := getMigrationsDir()
-	if _, err := os.Stat(migrationsDir); os.IsNotExist(err) {
-		return fmt.Errorf("迁移目录不存在: %s", migrationsDir)
-	}
-
-	goose.SetDialect("sqlite3")
-	if err := goose.Up(sqlDB, migrationsDir); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func getMigrationsDir() string {
-	_, filename, _, ok := runtime.Caller(0)
-	if ok {
-		dir := filepath.Join(filepath.Dir(filename), "..", "..", "migrations")
-		if abs, err := filepath.Abs(dir); err == nil {
-			return abs
-		}
-	}
-	return "./migrations"
-}
-
-func closeDB(db *gorm.DB) {
-	sqlDB, err := db.DB()
-	if err != nil {
-		return
-	}
-	sqlDB.Close()
-}
-
 func setupRoutes(r *gin.Engine, proxyHandler *handler.ProxyHandler, providerHandler *handler.ProviderHandler, modelHandler *handler.ModelHandler, statsHandler *handler.StatsHandler) {
 	r.Any("/v1/*path", proxyHandler.HandleProxy)
 
diff --git a/backend/cmd/server/main.go b/backend/cmd/server/main.go
index a604401..2bf8008 100644
--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -7,22 +7,17 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
-	"path/filepath"
-	"runtime"
 	"syscall"
 	"time"
 
 	"github.com/gin-gonic/gin"
-	"github.com/pressly/goose/v3"
 	"go.uber.org/zap"
-	"gorm.io/driver/sqlite"
-	"gorm.io/gorm"
-	"gorm.io/gorm/logger"
 
 	"nex/backend/internal/config"
 	"nex/backend/internal/conversion"
 	"nex/backend/internal/conversion/anthropic"
 	"nex/backend/internal/conversion/openai"
+	"nex/backend/internal/database"
 	"nex/backend/internal/handler"
 	"nex/backend/internal/handler/middleware"
 	"nex/backend/internal/provider"
@@ -32,16 +27,13 @@ import (
 )
 
 func main() {
-	// 1. 加载配置（已包含 CLI 参数解析、环境变量绑定、配置文件读取和验证）
 	cfg, err := config.LoadConfig()
 	if err != nil {
 		log.Fatalf("加载配置失败: %v", err)
 	}
 
-	// 2. 打印配置摘要
 	cfg.PrintSummary()
 
-	// 3. 初始化日志
 	zapLogger, err := pkgLogger.New(pkgLogger.Config{
 		Level:      cfg.Log.Level,
 		Path:       cfg.Log.Path,
@@ -55,37 +47,31 @@ func main() {
 	}
 	defer zapLogger.Sync()
 
-	// 3. 初始化数据库
-	db, err := initDatabase(cfg)
+	db, err := database.Init(&cfg.Database, zapLogger)
 	if err != nil {
 		zapLogger.Fatal("初始化数据库失败", zap.String("error", err.Error()))
 	}
-	defer closeDB(db)
+	defer database.Close(db)
 
-	// 4. 初始化 repository 层
 	providerRepo := repository.NewProviderRepository(db)
 	modelRepo := repository.NewModelRepository(db)
 	statsRepo := repository.NewStatsRepository(db)
 
-	// 5. 初始化缓存
 	routingCache := service.NewRoutingCache(modelRepo, providerRepo, zapLogger)
 	if err := routingCache.Preload(); err != nil {
 		zapLogger.Warn("缓存预热失败，将使用懒加载", zap.Error(err))
 	}
 
-	// 6. 初始化统计缓冲
 	statsBuffer := service.NewStatsBuffer(statsRepo, zapLogger,
 		service.WithFlushInterval(5*time.Second),
 		service.WithFlushThreshold(100))
 	statsBuffer.Start()
 
-	// 7. 初始化 service 层
 	providerService := service.NewProviderService(providerRepo, modelRepo, routingCache)
 	modelService := service.NewModelService(modelRepo, providerRepo, routingCache)
 	routingService := service.NewRoutingService(routingCache)
 	statsService := service.NewStatsService(statsRepo, statsBuffer)
 
-	// 8. 创建 ConversionEngine
 	registry := conversion.NewMemoryRegistry()
 	if err := registry.Register(openai.NewAdapter()); err != nil {
 		zapLogger.Fatal("注册 OpenAI 适配器失败", zap.String("error", err.Error()))
@@ -95,16 +81,13 @@ func main() {
 	}
 	engine := conversion.NewConversionEngine(registry, zapLogger)
 
-	// 9. 初始化 provider client
 	providerClient := provider.NewClient()
 
-	// 10. 初始化 handler 层
 	proxyHandler := handler.NewProxyHandler(engine, providerClient, routingService, providerService, statsService)
 	providerHandler := handler.NewProviderHandler(providerService)
 	modelHandler := handler.NewModelHandler(modelService)
 	statsHandler := handler.NewStatsHandler(statsService)
 
-	// 11. 创建 Gin 引擎
 	gin.SetMode(gin.ReleaseMode)
 	r := gin.New()
 
@@ -115,9 +98,8 @@ func main() {
 
 	setupRoutes(r, proxyHandler, providerHandler, modelHandler, statsHandler)
 
-	// 12. 启动服务器
 	srv := &http.Server{
-		Addr:         formatAddr(cfg.Server.Port),
+		Addr:         fmt.Sprintf(":%d", cfg.Server.Port),
 		Handler:      r,
 		ReadTimeout:  cfg.Server.ReadTimeout,
 		WriteTimeout: cfg.Server.WriteTimeout,
@@ -148,83 +130,9 @@ func main() {
 	zapLogger.Info("服务器已关闭")
 }
 
-func initDatabase(cfg *config.Config) (*gorm.DB, error) {
-	db, err := gorm.Open(sqlite.Open(cfg.Database.Path), &gorm.Config{
-		Logger: logger.Default.LogMode(logger.Info),
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	if err := runMigrations(db); err != nil {
-		return nil, fmt.Errorf("数据库迁移失败: %w", err)
-	}
-
-	if err := db.Exec("PRAGMA journal_mode=WAL").Error; err != nil {
-		log.Printf("警告: 启用 WAL 模式失败: %v", err)
-	}
-
-	sqlDB, err := db.DB()
-	if err != nil {
-		return nil, err
-	}
-	sqlDB.SetMaxIdleConns(cfg.Database.MaxIdleConns)
-	sqlDB.SetMaxOpenConns(cfg.Database.MaxOpenConns)
-	sqlDB.SetConnMaxLifetime(cfg.Database.ConnMaxLifetime)
-
-	log.Printf("数据库连接池配置: MaxIdle=%d, MaxOpen=%d, MaxLifetime=%v",
-		cfg.Database.MaxIdleConns, cfg.Database.MaxOpenConns, cfg.Database.ConnMaxLifetime)
-
-	return db, nil
-}
-
-func runMigrations(db *gorm.DB) error {
-	sqlDB, err := db.DB()
-	if err != nil {
-		return err
-	}
-
-	migrationsDir := getMigrationsDir()
-	if _, err := os.Stat(migrationsDir); os.IsNotExist(err) {
-		return fmt.Errorf("迁移目录不存在: %s", migrationsDir)
-	}
-
-	goose.SetDialect("sqlite3")
-	if err := goose.Up(sqlDB, migrationsDir); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func getMigrationsDir() string {
-	_, filename, _, ok := runtime.Caller(0)
-	if ok {
-		dir := filepath.Join(filepath.Dir(filename), "..", "..", "migrations")
-		if abs, err := filepath.Abs(dir); err == nil {
-			return abs
-		}
-	}
-	return "./migrations"
-}
-
-func closeDB(db *gorm.DB) {
-	sqlDB, err := db.DB()
-	if err != nil {
-		return
-	}
-	sqlDB.Close()
-}
-
-func formatAddr(port int) string {
-	return fmt.Sprintf(":%d", port)
-}
-
 func setupRoutes(r *gin.Engine, proxyHandler *handler.ProxyHandler, providerHandler *handler.ProviderHandler, modelHandler *handler.ModelHandler, statsHandler *handler.StatsHandler) {
-	// 统一代理入口: /{protocol}/{path}
 	r.Any("/:protocol/*path", proxyHandler.HandleProxy)
 
-	// 供应商管理 API
 	providers := r.Group("/api/providers")
 	{
 		providers.GET("", providerHandler.ListProviders)
@@ -234,7 +142,6 @@ func setupRoutes(r *gin.Engine, proxyHandler *handler.ProxyHandler, providerHand
 		providers.DELETE("/:id", providerHandler.DeleteProvider)
 	}
 
-	// 模型管理 API
 	models := r.Group("/api/models")
 	{
 		models.GET("", modelHandler.ListModels)
@@ -244,14 +151,12 @@ func setupRoutes(r *gin.Engine, proxyHandler *handler.ProxyHandler, providerHand
 		models.DELETE("/:id", modelHandler.DeleteModel)
 	}
 
-	// 统计查询 API
 	stats := r.Group("/api/stats")
 	{
 		stats.GET("", statsHandler.GetStats)
 		stats.GET("/aggregate", statsHandler.AggregateStats)
 	}
 
-	// 健康检查
 	r.GET("/health", func(c *gin.Context) {
 		c.JSON(200, gin.H{"status": "ok"})
 	})
diff --git a/backend/go.mod b/backend/go.mod
index 7ce3c5f..f56da25 100644
--- a/backend/go.mod
+++ b/backend/go.mod
@@ -24,6 +24,7 @@ require (
 	go.uber.org/zap v1.27.1
 	gopkg.in/lumberjack.v2 v2.0.0
 	gopkg.in/yaml.v3 v3.0.1
+	gorm.io/driver/mysql v1.6.0
 	gorm.io/driver/sqlite v1.6.0
 	gorm.io/gorm v1.31.1
 	nex/embedfs v0.0.0-00010101000000-000000000000
@@ -32,6 +33,7 @@ require (
 require (
 	4d63.com/gocheckcompilerdirectives v1.3.0 // indirect
 	4d63.com/gochecknoglobals v0.2.2 // indirect
+	filippo.io/edwards25519 v1.2.0 // indirect
 	github.com/4meepo/tagalign v1.4.2 // indirect
 	github.com/Abirdcfly/dupword v0.1.3 // indirect
 	github.com/Antonboom/errname v1.0.0 // indirect
@@ -90,6 +92,7 @@ require (
 	github.com/go-critic/go-critic v0.12.0 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
+	github.com/go-sql-driver/mysql v1.9.3 // indirect
 	github.com/go-stack/stack v1.8.0 // indirect
 	github.com/go-toolsmith/astcast v1.1.0 // indirect
 	github.com/go-toolsmith/astcopy v1.1.0 // indirect
diff --git a/backend/go.sum b/backend/go.sum
index 9c89ceb..c99656f 100644
--- a/backend/go.sum
+++ b/backend/go.sum
@@ -35,6 +35,8 @@ cloud.google.com/go/storage v1.6.0/go.mod h1:N7U0C8pVQ/+NIKOBQyamJIeKQKkZ+mxpohl
 cloud.google.com/go/storage v1.8.0/go.mod h1:Wv1Oy7z6Yz3DshWRJFhqM/UCfaWIRTdp0RXyy7KQOVs=
 cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9ullr3+Kg0=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
+filippo.io/edwards25519 v1.2.0 h1:crnVqOiS4jqYleHd9vaKZ+HKtHfllngJIiOpNpoJsjo=
+filippo.io/edwards25519 v1.2.0/go.mod h1:xzAOLCNug/yB62zG1bQ8uziwrIqIuxhctzJT18Q77mc=
 github.com/4meepo/tagalign v1.4.2 h1:0hcLHPGMjDyM1gHG58cS73aQF8J4TdVR96TZViorO9E=
 github.com/4meepo/tagalign v1.4.2/go.mod h1:+p4aMyFM+ra7nb41CnFG6aSDXqRxU/w1VQqScKqDARI=
 github.com/Abirdcfly/dupword v0.1.3 h1:9Pa1NuAsZvpFPi9Pqkd93I7LIYRURj+A//dFd5tgBeE=
@@ -206,6 +208,8 @@ github.com/go-playground/validator/v10 v10.30.2 h1:JiFIMtSSHb2/XBUbWM4i/MpeQm9ZK
 github.com/go-playground/validator/v10 v10.30.2/go.mod h1:mAf2pIOVXjTEBrwUMGKkCWKKPs9NheYGabeB04txQSc=
 github.com/go-quicktest/qt v1.101.0 h1:O1K29Txy5P2OK0dGo59b7b0LR6wKfIhttaAhHUyn7eI=
 github.com/go-quicktest/qt v1.101.0/go.mod h1:14Bz/f7NwaXPtdYEgzsx46kqSxVwTbzVZsDC26tQJow=
+github.com/go-sql-driver/mysql v1.9.3 h1:U/N249h2WzJ3Ukj8SowVFjdtZKfu9vlLZxjPXV1aweo=
+github.com/go-sql-driver/mysql v1.9.3/go.mod h1:qn46aNg1333BRMNU69Lq93t8du/dwxI64Gl8i5p1WMU=
 github.com/go-stack/stack v1.8.0 h1:5SgMzNM5HxrEjV0ww2lTmX6E2Izsfxas4+YHWRs3Lsk=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
@@ -1052,6 +1056,8 @@ gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gorm.io/driver/mysql v1.6.0 h1:eNbLmNTpPpTOVZi8MMxCi2aaIm0ZpInbORNXDwyLGvg=
+gorm.io/driver/mysql v1.6.0/go.mod h1:D/oCC2GWK3M/dqoLxnOlaNKmXz8WNTfcS9y5ovaSqKo=
 gorm.io/driver/sqlite v1.6.0 h1:WHRRrIiulaPiPFmDcod6prc4l2VGVWHz80KspNsxSfQ=
 gorm.io/driver/sqlite v1.6.0/go.mod h1:AO9V1qIQddBESngQUKWL9yoH93HIeA1X6V633rBwyT8=
 gorm.io/gorm v1.31.1 h1:7CA8FTFz/gRfgqgpeKIBcervUn3xSyPUmr6B2WXJ7kg=
diff --git a/backend/internal/config/config.go b/backend/internal/config/config.go
index 8bd13a0..391535d 100644
--- a/backend/internal/config/config.go
+++ b/backend/internal/config/config.go
@@ -32,7 +32,13 @@ type ServerConfig struct {
 
 // DatabaseConfig 数据库配置
 type DatabaseConfig struct {
-	Path            string        `yaml:"path" mapstructure:"path" validate:"required"`
+	Driver          string        `yaml:"driver" mapstructure:"driver" validate:"required,oneof=sqlite mysql"`
+	Path            string        `yaml:"path" mapstructure:"path" validate:"required_if=Driver sqlite"`
+	Host            string        `yaml:"host" mapstructure:"host" validate:"required_if=Driver mysql"`
+	Port            int           `yaml:"port" mapstructure:"port" validate:"required_if=Driver mysql,min=1,max=65535"`
+	User            string        `yaml:"user" mapstructure:"user" validate:"required_if=Driver mysql"`
+	Password        string        `yaml:"password" mapstructure:"password"`
+	DBName          string        `yaml:"dbname" mapstructure:"dbname" validate:"required_if=Driver mysql"`
 	MaxIdleConns    int           `yaml:"max_idle_conns" mapstructure:"max_idle_conns" validate:"required,min=1"`
 	MaxOpenConns    int           `yaml:"max_open_conns" mapstructure:"max_open_conns" validate:"required,min=1"`
 	ConnMaxLifetime time.Duration `yaml:"conn_max_lifetime" mapstructure:"conn_max_lifetime" validate:"required"`
@@ -61,7 +67,13 @@ func DefaultConfig() *Config {
 			WriteTimeout: 30 * time.Second,
 		},
 		Database: DatabaseConfig{
+			Driver:          "sqlite",
 			Path:            filepath.Join(nexDir, "config.db"),
+			Host:            "",
+			Port:            3306,
+			User:            "",
+			Password:        "",
+			DBName:          "nex",
 			MaxIdleConns:    10,
 			MaxOpenConns:    100,
 			ConnMaxLifetime: 1 * time.Hour,
@@ -117,7 +129,13 @@ func setupDefaults(v *viper.Viper) {
 	v.SetDefault("server.read_timeout", "30s")
 	v.SetDefault("server.write_timeout", "30s")
 
+	v.SetDefault("database.driver", "sqlite")
 	v.SetDefault("database.path", filepath.Join(nexDir, "config.db"))
+	v.SetDefault("database.host", "")
+	v.SetDefault("database.port", 3306)
+	v.SetDefault("database.user", "")
+	v.SetDefault("database.password", "")
+	v.SetDefault("database.dbname", "nex")
 	v.SetDefault("database.max_idle_conns", 10)
 	v.SetDefault("database.max_open_conns", 100)
 	v.SetDefault("database.conn_max_lifetime", "1h")
@@ -138,7 +156,13 @@ func setupFlags(v *viper.Viper, flagSet *pflag.FlagSet) {
 	flagSet.Duration("server-read-timeout", 0, "读超时")
 	flagSet.Duration("server-write-timeout", 0, "写超时")
 
+	flagSet.String("database-driver", "", "数据库驱动：sqlite/mysql")
 	flagSet.String("database-path", "", "数据库文件路径")
+	flagSet.String("database-host", "", "MySQL 主机地址")
+	flagSet.Int("database-port", 0, "MySQL 端口")
+	flagSet.String("database-user", "", "MySQL 用户名")
+	flagSet.String("database-password", "", "MySQL 密码")
+	flagSet.String("database-dbname", "", "MySQL 数据库名")
 	flagSet.Int("database-max-idle-conns", 0, "最大空闲连接数")
 	flagSet.Int("database-max-open-conns", 0, "最大打开连接数")
 	flagSet.Duration("database-conn-max-lifetime", 0, "连接最大生命周期")
@@ -156,7 +180,13 @@ func setupFlags(v *viper.Viper, flagSet *pflag.FlagSet) {
 	v.BindPFlag("server.read_timeout", flagSet.Lookup("server-read-timeout"))
 	v.BindPFlag("server.write_timeout", flagSet.Lookup("server-write-timeout"))
 
+	v.BindPFlag("database.driver", flagSet.Lookup("database-driver"))
 	v.BindPFlag("database.path", flagSet.Lookup("database-path"))
+	v.BindPFlag("database.host", flagSet.Lookup("database-host"))
+	v.BindPFlag("database.port", flagSet.Lookup("database-port"))
+	v.BindPFlag("database.user", flagSet.Lookup("database-user"))
+	v.BindPFlag("database.password", flagSet.Lookup("database-password"))
+	v.BindPFlag("database.dbname", flagSet.Lookup("database-dbname"))
 	v.BindPFlag("database.max_idle_conns", flagSet.Lookup("database-max-idle-conns"))
 	v.BindPFlag("database.max_open_conns", flagSet.Lookup("database-max-open-conns"))
 	v.BindPFlag("database.conn_max_lifetime", flagSet.Lookup("database-conn-max-lifetime"))
@@ -268,7 +298,7 @@ func SaveConfig(cfg *Config) error {
 		return appErrors.Wrap(appErrors.ErrInternal, err)
 	}
 
-	return os.WriteFile(configPath, data, 0644)
+	return os.WriteFile(configPath, data, 0600)
 }
 
 // Validate validates the config
@@ -285,7 +315,13 @@ func (c *Config) PrintSummary() {
 	fmt.Println("\nAI Gateway 启动配置")
 	fmt.Println("==================")
 	fmt.Printf("服务器端口:     %d\n", c.Server.Port)
-	fmt.Printf("数据库路径:     %s\n", c.Database.Path)
+	if c.Database.Driver == "mysql" {
+		fmt.Printf("数据库类型:     mysql\n")
+		fmt.Printf("数据库地址:     %s:%d/%s\n", c.Database.Host, c.Database.Port, c.Database.DBName)
+	} else {
+		fmt.Printf("数据库类型:     sqlite\n")
+		fmt.Printf("数据库路径:     %s\n", c.Database.Path)
+	}
 	fmt.Printf("日志级别:       %s\n", c.Log.Level)
 	fmt.Println("\n配置来源:")
 	configPath, _ := GetConfigPath()
diff --git a/backend/internal/config/config_test.go b/backend/internal/config/config_test.go
index cc390bc..b4a58e4 100644
--- a/backend/internal/config/config_test.go
+++ b/backend/internal/config/config_test.go
@@ -19,6 +19,12 @@ func TestDefaultConfig(t *testing.T) {
 	assert.Equal(t, 30*time.Second, cfg.Server.ReadTimeout)
 	assert.Equal(t, 30*time.Second, cfg.Server.WriteTimeout)
 
+	assert.Equal(t, "sqlite", cfg.Database.Driver)
+	assert.Equal(t, "", cfg.Database.Host)
+	assert.Equal(t, 3306, cfg.Database.Port)
+	assert.Equal(t, "", cfg.Database.User)
+	assert.Equal(t, "", cfg.Database.Password)
+	assert.Equal(t, "nex", cfg.Database.DBName)
 	assert.Equal(t, 10, cfg.Database.MaxIdleConns)
 	assert.Equal(t, 100, cfg.Database.MaxOpenConns)
 	assert.Equal(t, 1*time.Hour, cfg.Database.ConnMaxLifetime)
@@ -86,11 +92,76 @@ func TestConfig_Validate(t *testing.T) {
 			wantErr: false,
 		},
 		{
-			name:    "数据库路径为空无效",
+			name:    "SQLite模式路径为空无效",
 			modify:  func(c *Config) { c.Database.Path = "" },
 			wantErr: true,
 			errMsg:  "配置验证失败",
 		},
+		{
+			name:    "driver值不合法",
+			modify:  func(c *Config) { c.Database.Driver = "postgres" },
+			wantErr: true,
+			errMsg:  "配置验证失败",
+		},
+		{
+			name: "MySQL配置有效",
+			modify: func(c *Config) {
+				c.Database.Driver = "mysql"
+				c.Database.Host = "localhost"
+				c.Database.Port = 3306
+				c.Database.User = "root"
+				c.Database.DBName = "nex"
+				c.Database.Path = ""
+			},
+			wantErr: false,
+		},
+		{
+			name: "MySQL模式host为空无效",
+			modify: func(c *Config) {
+				c.Database.Driver = "mysql"
+				c.Database.Host = ""
+				c.Database.User = "root"
+				c.Database.DBName = "nex"
+				c.Database.Path = ""
+			},
+			wantErr: true,
+			errMsg:  "配置验证失败",
+		},
+		{
+			name: "MySQL模式user为空无效",
+			modify: func(c *Config) {
+				c.Database.Driver = "mysql"
+				c.Database.Host = "localhost"
+				c.Database.User = ""
+				c.Database.DBName = "nex"
+				c.Database.Path = ""
+			},
+			wantErr: true,
+			errMsg:  "配置验证失败",
+		},
+		{
+			name: "MySQL模式dbname为空无效",
+			modify: func(c *Config) {
+				c.Database.Driver = "mysql"
+				c.Database.Host = "localhost"
+				c.Database.User = "root"
+				c.Database.DBName = ""
+				c.Database.Path = ""
+			},
+			wantErr: true,
+			errMsg:  "配置验证失败",
+		},
+		{
+			name: "MySQL模式忽略path字段",
+			modify: func(c *Config) {
+				c.Database.Driver = "mysql"
+				c.Database.Host = "localhost"
+				c.Database.User = "root"
+				c.Database.DBName = "nex"
+				c.Database.Path = ""
+			},
+			wantErr: false,
+		},
 	}
 
 	for _, tt := range tests {
@@ -140,7 +211,10 @@ func TestSaveAndLoadConfig(t *testing.T) {
 			WriteTimeout: 20 * time.Second,
 		},
 		Database: DatabaseConfig{
+			Driver:          "sqlite",
 			Path:            filepath.Join(dir, "test.db"),
+			Port:            3306,
+			DBName:          "nex",
 			MaxIdleConns:    5,
 			MaxOpenConns:    50,
 			ConnMaxLifetime: 30 * time.Minute,
@@ -210,6 +284,9 @@ func TestConfigPriority(t *testing.T) {
 		assert.Equal(t, 9826, cfg.Server.Port)
 		assert.Equal(t, 30*time.Second, cfg.Server.ReadTimeout)
 		assert.Equal(t, 30*time.Second, cfg.Server.WriteTimeout)
+		assert.Equal(t, "sqlite", cfg.Database.Driver)
+		assert.Equal(t, 3306, cfg.Database.Port)
+		assert.Equal(t, "nex", cfg.Database.DBName)
 		assert.Equal(t, 10, cfg.Database.MaxIdleConns)
 		assert.Equal(t, 100, cfg.Database.MaxOpenConns)
 		assert.Equal(t, 1*time.Hour, cfg.Database.ConnMaxLifetime)
@@ -222,11 +299,19 @@ func TestConfigPriority(t *testing.T) {
 }
 
 func TestPrintSummary(t *testing.T) {
-	// 测试配置摘要输出
-	t.Run("打印配置摘要", func(t *testing.T) {
+	t.Run("SQLite模式摘要", func(t *testing.T) {
 		cfg := DefaultConfig()
-		// PrintSummary 只是打印，不会返回错误
-		// 这里主要验证不会 panic
+		assert.NotPanics(t, func() {
+			cfg.PrintSummary()
+		})
+	})
+	t.Run("MySQL模式摘要", func(t *testing.T) {
+		cfg := DefaultConfig()
+		cfg.Database.Driver = "mysql"
+		cfg.Database.Host = "db.example.com"
+		cfg.Database.Port = 3306
+		cfg.Database.User = "nex"
+		cfg.Database.DBName = "nex"
 		assert.NotPanics(t, func() {
 			cfg.PrintSummary()
 		})
diff --git a/backend/internal/config/models.go b/backend/internal/config/models.go
index 628d184..8add81e 100644
--- a/backend/internal/config/models.go
+++ b/backend/internal/config/models.go
@@ -29,8 +29,8 @@ type Model struct {
 // UsageStats 用量统计
 type UsageStats struct {
 	ID           uint      `gorm:"primaryKey;autoIncrement" json:"id"`
-	ProviderID   string    `gorm:"not null;index" json:"provider_id"`
-	ModelName    string    `gorm:"not null;index" json:"model_name"`
+	ProviderID   string    `gorm:"not null;index;uniqueIndex:idx_provider_model_date" json:"provider_id"`
+	ModelName    string    `gorm:"not null;index;uniqueIndex:idx_provider_model_date" json:"model_name"`
 	RequestCount int       `gorm:"default:0" json:"request_count"`
 	Date         time.Time `gorm:"type:date;not null;uniqueIndex:idx_provider_model_date" json:"date"`
 }
diff --git a/backend/internal/database/database.go b/backend/internal/database/database.go
new file mode 100644
index 0000000..76661a5
--- /dev/null
+++ b/backend/internal/database/database.go
@@ -0,0 +1,126 @@
+package database
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/pressly/goose/v3"
+	"go.uber.org/zap"
+	"gorm.io/driver/mysql"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+
+	"nex/backend/internal/config"
+)
+
+func Init(cfg *config.DatabaseConfig, zapLogger *zap.Logger) (*gorm.DB, error) {
+	db, err := initDB(cfg)
+	if err != nil {
+		return nil, fmt.Errorf("初始化数据库失败: %w", err)
+	}
+
+	if err := runMigrations(db, cfg.Driver); err != nil {
+		return nil, fmt.Errorf("数据库迁移失败: %w", err)
+	}
+
+	configurePool(db, cfg)
+
+	return db, nil
+}
+
+func Close(db *gorm.DB) {
+	sqlDB, err := db.DB()
+	if err != nil {
+		return
+	}
+	sqlDB.Close()
+}
+
+func initDB(cfg *config.DatabaseConfig) (*gorm.DB, error) {
+	gormConfig := &gorm.Config{
+		Logger: logger.Default.LogMode(logger.Info),
+	}
+
+	switch cfg.Driver {
+	case "mysql":
+		dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=true&loc=Local",
+			cfg.User, cfg.Password, cfg.Host, cfg.Port, cfg.DBName)
+		return gorm.Open(mysql.Open(dsn), gormConfig)
+	default:
+		dbDir := filepath.Dir(cfg.Path)
+		if err := os.MkdirAll(dbDir, 0755); err != nil {
+			return nil, fmt.Errorf("创建数据库目录失败: %w", err)
+		}
+		return gorm.Open(sqlite.Open(cfg.Path), gormConfig)
+	}
+}
+
+func runMigrations(db *gorm.DB, driver string) error {
+	sqlDB, err := db.DB()
+	if err != nil {
+		return err
+	}
+
+	migrationsDir := getMigrationsDir(driver)
+	if _, err := os.Stat(migrationsDir); os.IsNotExist(err) {
+		return fmt.Errorf("迁移目录不存在: %s", migrationsDir)
+	}
+
+	gooseDialect := "sqlite3"
+	migrationsSubDir := "sqlite"
+	if driver == "mysql" {
+		gooseDialect = "mysql"
+		migrationsSubDir = "mysql"
+	}
+
+	goose.SetDialect(gooseDialect)
+	if err := goose.Up(sqlDB, migrationsDir); err != nil {
+		return err
+	}
+
+	log.Printf("使用 %s 方言执行迁移，目录: %s", gooseDialect, migrationsSubDir)
+	return nil
+}
+
+func configurePool(db *gorm.DB, cfg *config.DatabaseConfig) {
+	if cfg.Driver == "sqlite" {
+		if err := db.Exec("PRAGMA journal_mode=WAL").Error; err != nil {
+			log.Printf("警告: 启用 WAL 模式失败: %v", err)
+		}
+	}
+
+	sqlDB, err := db.DB()
+	if err != nil {
+		return
+	}
+	sqlDB.SetMaxIdleConns(cfg.MaxIdleConns)
+	sqlDB.SetMaxOpenConns(cfg.MaxOpenConns)
+	sqlDB.SetConnMaxLifetime(cfg.ConnMaxLifetime)
+
+	log.Printf("数据库连接池配置: MaxIdle=%d, MaxOpen=%d, MaxLifetime=%v",
+		cfg.MaxIdleConns, cfg.MaxOpenConns, cfg.ConnMaxLifetime)
+}
+
+func getMigrationsDir(driver string) string {
+	_, filename, _, ok := runtime.Caller(0)
+	if ok {
+		subDir := "sqlite"
+		if driver == "mysql" {
+			subDir = "mysql"
+		}
+		dir := filepath.Join(filepath.Dir(filename), "..", "..", "migrations", subDir)
+		if abs, err := filepath.Abs(dir); err == nil {
+			return abs
+		}
+	}
+	return "./migrations"
+}
+
+func BuildDSN(cfg *config.DatabaseConfig) string {
+	return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=true&loc=Local",
+		cfg.User, cfg.Password, cfg.Host, cfg.Port, cfg.DBName)
+}
diff --git a/backend/internal/database/database_test.go b/backend/internal/database/database_test.go
new file mode 100644
index 0000000..ddb5669
--- /dev/null
+++ b/backend/internal/database/database_test.go
@@ -0,0 +1,75 @@
+package database
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"nex/backend/internal/config"
+)
+
+func TestInit_SQLite(t *testing.T) {
+	dir := t.TempDir()
+	cfg := &config.DatabaseConfig{
+		Driver:          "sqlite",
+		Path:            filepath.Join(dir, "test.db"),
+		MaxIdleConns:    5,
+		MaxOpenConns:    10,
+		ConnMaxLifetime: 0,
+	}
+
+	db, err := Init(cfg, nil)
+	require.NoError(t, err)
+	require.NotNil(t, db)
+	defer Close(db)
+
+	sqlDB, err := db.DB()
+	require.NoError(t, err)
+	require.NotNil(t, sqlDB)
+}
+
+func TestClose(t *testing.T) {
+	dir := t.TempDir()
+	cfg := &config.DatabaseConfig{
+		Driver:          "sqlite",
+		Path:            filepath.Join(dir, "test.db"),
+		MaxIdleConns:    5,
+		MaxOpenConns:    10,
+		ConnMaxLifetime: 0,
+	}
+
+	db, err := Init(cfg, nil)
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	Close(db)
+}
+
+func TestBuildDSN(t *testing.T) {
+	cfg := &config.DatabaseConfig{
+		Driver:   "mysql",
+		Host:     "db.example.com",
+		Port:     3306,
+		User:     "nexuser",
+		Password: "secretpass",
+		DBName:   "nexdb",
+	}
+
+	dsn := BuildDSN(cfg)
+	assert.Equal(t, "nexuser:secretpass@tcp(db.example.com:3306)/nexdb?charset=utf8mb4&parseTime=true&loc=Local", dsn)
+}
+
+func TestBuildDSN_EmptyPassword(t *testing.T) {
+	cfg := &config.DatabaseConfig{
+		Driver: "mysql",
+		Host:   "localhost",
+		Port:   3306,
+		User:   "root",
+		DBName: "nex",
+	}
+
+	dsn := BuildDSN(cfg)
+	assert.Equal(t, "root:@tcp(localhost:3306)/nex?charset=utf8mb4&parseTime=true&loc=Local", dsn)
+}
diff --git a/backend/internal/repository/stats_repo_impl.go b/backend/internal/repository/stats_repo_impl.go
index 7692b33..ca9e7d8 100644
--- a/backend/internal/repository/stats_repo_impl.go
+++ b/backend/internal/repository/stats_repo_impl.go
@@ -1,10 +1,10 @@
 package repository
 
 import (
-	"errors"
 	"time"
 
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 
 	"nex/backend/internal/config"
 	"nex/backend/internal/domain"
@@ -22,47 +22,43 @@ func (r *statsRepository) Record(providerID, modelName string) error {
 	today := time.Now().Format("2006-01-02")
 	todayTime, _ := time.Parse("2006-01-02", today)
 
-	return r.db.Transaction(func(tx *gorm.DB) error {
-		var stats config.UsageStats
-		err := tx.Where("provider_id = ? AND model_name = ? AND date = ?",
-			providerID, modelName, todayTime).First(&stats).Error
+	stats := config.UsageStats{
+		ProviderID:   providerID,
+		ModelName:    modelName,
+		RequestCount: 1,
+		Date:         todayTime,
+	}
 
-		if errors.Is(err, gorm.ErrRecordNotFound) {
-			stats = config.UsageStats{
-				ProviderID:   providerID,
-				ModelName:    modelName,
-				RequestCount: 1,
-				Date:         todayTime,
-			}
-			return tx.Create(&stats).Error
-		} else if err != nil {
-			return err
-		}
-
-		return tx.Model(&stats).Update("request_count", gorm.Expr("request_count + 1")).Error
-	})
+	return r.db.Clauses(clause.OnConflict{
+		Columns: []clause.Column{
+			{Name: "provider_id"},
+			{Name: "model_name"},
+			{Name: "date"},
+		},
+		DoUpdates: clause.Assignments(map[string]interface{}{
+			"request_count": gorm.Expr("request_count + 1"),
+		}),
+	}).Create(&stats).Error
 }
 
 func (r *statsRepository) BatchUpdate(providerID, modelName string, date time.Time, delta int) error {
-	return r.db.Transaction(func(tx *gorm.DB) error {
-		var stats config.UsageStats
-		err := tx.Where("provider_id = ? AND model_name = ? AND date = ?",
-			providerID, modelName, date).First(&stats).Error
+	stats := config.UsageStats{
+		ProviderID:   providerID,
+		ModelName:    modelName,
+		RequestCount: delta,
+		Date:         date,
+	}
 
-		if errors.Is(err, gorm.ErrRecordNotFound) {
-			return tx.Create(&config.UsageStats{
-				ProviderID:   providerID,
-				ModelName:    modelName,
-				RequestCount: delta,
-				Date:         date,
-			}).Error
-		} else if err != nil {
-			return err
-		}
-
-		return tx.Model(&stats).
-			Update("request_count", gorm.Expr("request_count + ?", delta)).Error
-	})
+	return r.db.Clauses(clause.OnConflict{
+		Columns: []clause.Column{
+			{Name: "provider_id"},
+			{Name: "model_name"},
+			{Name: "date"},
+		},
+		DoUpdates: clause.Assignments(map[string]interface{}{
+			"request_count": gorm.Expr("request_count + ?", delta),
+		}),
+	}).Create(&stats).Error
 }
 
 func (r *statsRepository) Query(providerID, modelName string, startDate, endDate *time.Time) ([]domain.UsageStats, error) {
diff --git a/backend/migrations/mysql/20260421000001_initial_schema.sql b/backend/migrations/mysql/20260421000001_initial_schema.sql
new file mode 100644
index 0000000..85f64db
--- /dev/null
+++ b/backend/migrations/mysql/20260421000001_initial_schema.sql
@@ -0,0 +1,44 @@
+-- +goose Up
+-- MySQL 方言初始迁移：providers、models、usage_stats 完整表结构
+
+CREATE TABLE IF NOT EXISTS providers (
+    id VARCHAR(36) PRIMARY KEY,
+    name VARCHAR(255) NOT NULL,
+    api_key VARCHAR(255) NOT NULL,
+    base_url VARCHAR(255) NOT NULL,
+    protocol VARCHAR(50) DEFAULT 'openai',
+    enabled BOOLEAN DEFAULT TRUE,
+    created_at DATETIME(3),
+    updated_at DATETIME(3)
+);
+
+CREATE TABLE IF NOT EXISTS models (
+    id VARCHAR(36) PRIMARY KEY,
+    provider_id VARCHAR(36) NOT NULL,
+    model_name VARCHAR(255) NOT NULL,
+    enabled BOOLEAN DEFAULT TRUE,
+    created_at DATETIME(3),
+    FOREIGN KEY (provider_id) REFERENCES providers(id) ON DELETE CASCADE,
+    UNIQUE(provider_id, model_name)
+);
+
+CREATE TABLE IF NOT EXISTS usage_stats (
+    id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+    provider_id VARCHAR(36) NOT NULL,
+    model_name VARCHAR(255) NOT NULL,
+    request_count INT DEFAULT 0,
+    date DATE NOT NULL,
+    UNIQUE(provider_id, model_name, date)
+);
+
+CREATE INDEX idx_models_provider_id ON models(provider_id);
+CREATE INDEX idx_models_model_name ON models(model_name);
+CREATE INDEX idx_usage_stats_provider_model_date ON usage_stats(provider_id, model_name, date);
+
+-- +goose Down
+DROP INDEX IF EXISTS idx_usage_stats_provider_model_date ON usage_stats;
+DROP INDEX IF EXISTS idx_models_model_name ON models;
+DROP INDEX IF EXISTS idx_models_provider_id ON models;
+DROP TABLE IF EXISTS usage_stats;
+DROP TABLE IF EXISTS models;
+DROP TABLE IF EXISTS providers;
diff --git a/backend/migrations/20260421000001_initial_schema.sql b/backend/migrations/sqlite/20260421000001_initial_schema.sql
similarity index 100%
rename from backend/migrations/20260421000001_initial_schema.sql
rename to backend/migrations/sqlite/20260421000001_initial_schema.sql
diff --git a/backend/tests/config/config_test.go b/backend/tests/config/config_test.go
index d15bd16..ff55aa1 100644
--- a/backend/tests/config/config_test.go
+++ b/backend/tests/config/config_test.go
@@ -158,7 +158,10 @@ func TestSaveAndLoadConfig(t *testing.T) {
 			WriteTimeout: 45 * time.Second,
 		},
 		Database: config.DatabaseConfig{
+			Driver:          "sqlite",
 			Path:            filepath.Join(tmpDir, "test.db"),
+			Port:            3306,
+			DBName:          "nex",
 			MaxIdleConns:    15,
 			MaxOpenConns:    150,
 			ConnMaxLifetime: 2 * time.Hour,
diff --git a/backend/tests/mysql/concurrent_test.go b/backend/tests/mysql/concurrent_test.go
new file mode 100644
index 0000000..8aa7ff0
--- /dev/null
+++ b/backend/tests/mysql/concurrent_test.go
@@ -0,0 +1,158 @@
+//go:build mysql
+
+package mysql
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"nex/backend/internal/config"
+	"nex/backend/internal/repository"
+)
+
+func TestConcurrent_UsageStatsRecord(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	statsRepo := repository.NewStatsRepository(db)
+
+	providerID := "concurrent-test-provider"
+	modelName := "gpt-4"
+
+	concurrency := 10
+	var wg sync.WaitGroup
+	wg.Add(concurrency)
+
+	errChan := make(chan error, concurrency)
+
+	for i := 0; i < concurrency; i++ {
+		go func() {
+			defer wg.Done()
+			err := statsRepo.Record(providerID, modelName)
+			if err != nil {
+				errChan <- err
+			}
+		}()
+	}
+
+	wg.Wait()
+	close(errChan)
+
+	var errorCount int
+	uniqueErrors := make(map[string]int)
+	for err := range errChan {
+		errorCount++
+		uniqueErrors[err.Error()]++
+	}
+
+	t.Logf("并发 %d 次，错误 %d 次", concurrency, errorCount)
+	for errMsg, count := range uniqueErrors {
+		t.Logf("  错误: %s (出现 %d 次)", errMsg, count)
+	}
+
+	var stats config.UsageStats
+	err := db.Where("provider_id = ? AND model_name = ?", providerID, modelName).
+		First(&stats).Error
+	require.NoError(t, err, "应能查到 usage_stats 记录")
+
+	successCount := concurrency - errorCount
+	t.Logf("成功次数: %d, 最终 request_count: %d", successCount, stats.RequestCount)
+
+	assert.Equal(t, concurrency, stats.RequestCount, "request_count 应等于并发数，无数据丢失或重复")
+}
+
+func TestConcurrent_ProviderCreate(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	providerID := "concurrent-provider-id"
+	concurrency := 10
+
+	var wg sync.WaitGroup
+	wg.Add(concurrency)
+
+	successCount := 0
+	var mu sync.Mutex
+
+	for i := 0; i < concurrency; i++ {
+		go func() {
+			defer wg.Done()
+
+			provider := config.Provider{
+				ID:      providerID,
+				Name:    "Concurrent Provider",
+				APIKey:  "test-key",
+				BaseURL: "https://test.com",
+				Enabled: true,
+			}
+
+			err := db.Create(&provider).Error
+			if err == nil {
+				mu.Lock()
+				successCount++
+				mu.Unlock()
+			}
+		}()
+	}
+
+	wg.Wait()
+
+	assert.Equal(t, 1, successCount, "仅 1 个创建应成功")
+
+	var count int64
+	db.Model(&config.Provider{}).Where("id = ?", providerID).Count(&count)
+	assert.Equal(t, int64(1), count, "最终应有 1 条记录")
+}
+
+func TestConcurrent_ModelCreate(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	provider := config.Provider{
+		ID:      "concurrent-model-provider",
+		Name:    "Test Provider",
+		APIKey:  "test-key",
+		BaseURL: "https://test.com",
+		Enabled: true,
+	}
+	err := db.Create(&provider).Error
+	require.NoError(t, err, "创建 provider 应成功")
+
+	modelName := "gpt-4-concurrent"
+	concurrency := 10
+
+	var wg sync.WaitGroup
+	wg.Add(concurrency)
+
+	successCount := 0
+	var mu sync.Mutex
+
+	for i := 0; i < concurrency; i++ {
+		go func(idx int) {
+			defer wg.Done()
+
+			model := config.Model{
+				ID:         uuid.New().String(),
+				ProviderID: provider.ID,
+				ModelName:  modelName,
+				Enabled:    true,
+			}
+
+			err := db.Create(&model).Error
+			if err == nil {
+				mu.Lock()
+				successCount++
+				mu.Unlock()
+			}
+		}(i)
+	}
+
+	wg.Wait()
+
+	assert.Equal(t, 1, successCount, "仅 1 个创建应成功")
+
+	var count int64
+	db.Model(&config.Model{}).Where("provider_id = ? AND model_name = ?", provider.ID, modelName).Count(&count)
+	assert.Equal(t, int64(1), count, "最终应有 1 条记录")
+}
diff --git a/backend/tests/mysql/constraint_test.go b/backend/tests/mysql/constraint_test.go
new file mode 100644
index 0000000..7923c23
--- /dev/null
+++ b/backend/tests/mysql/constraint_test.go
@@ -0,0 +1,130 @@
+//go:build mysql
+
+package mysql
+
+import (
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/gorm"
+
+	"nex/backend/internal/config"
+)
+
+func TestConstraint_ForeignKeyEnforced(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	model := config.Model{
+		ID:         "test-model-id",
+		ProviderID: "non-existent-provider",
+		ModelName:  "gpt-4",
+		Enabled:    true,
+	}
+
+	err := db.Create(&model).Error
+	assert.Error(t, err, "创建 model 时 provider_id 不存在应失败")
+	assert.Contains(t, err.Error(), "foreign key constraint", "错误应为外键约束错误")
+}
+
+func TestConstraint_CascadeDelete(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	provider := config.Provider{
+		ID:      "test-provider-cascade",
+		Name:    "Test Provider",
+		APIKey:  "test-key",
+		BaseURL: "https://test.com",
+		Enabled: true,
+	}
+	err := db.Create(&provider).Error
+	require.NoError(t, err, "创建 provider 应成功")
+
+	model := config.Model{
+		ID:         "test-model-cascade",
+		ProviderID: provider.ID,
+		ModelName:  "gpt-4",
+		Enabled:    true,
+	}
+	err = db.Create(&model).Error
+	require.NoError(t, err, "创建 model 应成功")
+
+	err = db.Delete(&provider).Error
+	require.NoError(t, err, "删除 provider 应成功")
+
+	var count int64
+	err = db.Model(&config.Model{}).Where("provider_id = ?", provider.ID).Count(&count).Error
+	require.NoError(t, err)
+	assert.Equal(t, int64(0), count, "删除 provider 后其 models 应被级联删除")
+}
+
+func TestConstraint_UniqueProviderModel(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	provider := config.Provider{
+		ID:      "test-provider-unique",
+		Name:    "Test Provider",
+		APIKey:  "test-key",
+		BaseURL: "https://test.com",
+		Enabled: true,
+	}
+	err := db.Create(&provider).Error
+	require.NoError(t, err, "创建 provider 应成功")
+
+	model1 := config.Model{
+		ID:         "test-model-unique-1",
+		ProviderID: provider.ID,
+		ModelName:  "gpt-4",
+		Enabled:    true,
+	}
+	err = db.Create(&model1).Error
+	require.NoError(t, err, "创建第一个 model 应成功")
+
+	model2 := config.Model{
+		ID:         "test-model-unique-2",
+		ProviderID: provider.ID,
+		ModelName:  "gpt-4",
+		Enabled:    true,
+	}
+	err = db.Create(&model2).Error
+	assert.Error(t, err, "创建相同 (provider_id, model_name) 的 model 应失败")
+	assert.True(t, errors.Is(err, gorm.ErrDuplicatedKey) || 
+		(err != nil && (err.Error() == "Error 1062" || containsDuplicateError(err.Error()))),
+		"错误应为唯一约束错误")
+}
+
+func TestConstraint_UniqueUsageStats(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	today := time.Now().Format("2006-01-02")
+	todayTime, _ := time.Parse("2006-01-02", today)
+
+	providerID := "test-provider-unique-stats"
+
+	stats1 := config.UsageStats{
+		ProviderID:   providerID,
+		ModelName:    "gpt-4",
+		RequestCount: 10,
+		Date:         todayTime,
+	}
+	err := db.Create(&stats1).Error
+	require.NoError(t, err, "创建第一个 usage_stats 应成功")
+
+	stats2 := config.UsageStats{
+		ProviderID:   providerID,
+		ModelName:    "gpt-4",
+		RequestCount: 20,
+		Date:         todayTime,
+	}
+	err = db.Create(&stats2).Error
+	assert.Error(t, err, "创建相同 (provider_id, model_name, date) 的 usage_stats 应失败")
+	assert.True(t, errors.Is(err, gorm.ErrDuplicatedKey) || 
+		(err != nil && (err.Error() == "Error 1062" || containsDuplicateError(err.Error()))),
+		"错误应为唯一约束错误")
+}
+
+func containsDuplicateError(errStr string) bool {
+	return len(errStr) > 0 && (errStr[0:8] == "Error 10" || errStr[0:5] == "Dupli")
+}
diff --git a/backend/tests/mysql/docker-compose.yml b/backend/tests/mysql/docker-compose.yml
new file mode 100644
index 0000000..3735f24
--- /dev/null
+++ b/backend/tests/mysql/docker-compose.yml
@@ -0,0 +1,21 @@
+version: '3.8'
+
+services:
+  mysql:
+    image: mysql:8.0
+    container_name: nex-mysql-test
+    environment:
+      MYSQL_ROOT_PASSWORD: testpass
+      MYSQL_DATABASE: nex_test
+      MYSQL_USER: nex_test
+      MYSQL_PASSWORD: testpass
+    ports:
+      - "13306:3306"
+    tmpfs:
+      - /var/lib/mysql
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost", "-u", "root", "-p$$MYSQL_ROOT_PASSWORD"]
+      interval: 1s
+      timeout: 5s
+      retries: 10
+      start_period: 10s
diff --git a/backend/tests/mysql/migration_test.go b/backend/tests/mysql/migration_test.go
new file mode 100644
index 0000000..acb677c
--- /dev/null
+++ b/backend/tests/mysql/migration_test.go
@@ -0,0 +1,126 @@
+//go:build mysql
+
+package mysql
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMigration_TablesExist(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	var tables []string
+	err := db.Raw("SHOW TABLES").Scan(&tables).Error
+	require.NoError(t, err)
+
+	expectedTables := []string{"providers", "models", "usage_stats"}
+	for _, expected := range expectedTables {
+		assert.Contains(t, tables, expected, "表 %s 应存在", expected)
+	}
+}
+
+func TestMigration_TableColumns(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	t.Run("providers 表字段", func(t *testing.T) {
+		var columns []struct {
+			Field string
+			Type  string
+			Null  string
+		}
+		err := db.Raw("SHOW COLUMNS FROM providers").Scan(&columns).Error
+		require.NoError(t, err)
+
+		columnMap := make(map[string]string)
+		for _, col := range columns {
+			columnMap[col.Field] = col.Type
+		}
+
+		assert.Contains(t, columnMap["id"], "varchar", "id 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["name"], "varchar", "name 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["api_key"], "varchar", "api_key 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["base_url"], "varchar", "base_url 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["protocol"], "varchar", "protocol 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["enabled"], "tinyint", "enabled 应为 TINYINT (BOOLEAN) 类型")
+		assert.Contains(t, columnMap["created_at"], "datetime", "created_at 应为 DATETIME 类型")
+		assert.Contains(t, columnMap["updated_at"], "datetime", "updated_at 应为 DATETIME 类型")
+	})
+
+	t.Run("models 表字段", func(t *testing.T) {
+		var columns []struct {
+			Field string
+			Type  string
+		}
+		err := db.Raw("SHOW COLUMNS FROM models").Scan(&columns).Error
+		require.NoError(t, err)
+
+		columnMap := make(map[string]string)
+		for _, col := range columns {
+			columnMap[col.Field] = col.Type
+		}
+
+		assert.Contains(t, columnMap["id"], "varchar", "id 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["provider_id"], "varchar", "provider_id 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["model_name"], "varchar", "model_name 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["enabled"], "tinyint", "enabled 应为 TINYINT (BOOLEAN) 类型")
+		assert.Contains(t, columnMap["created_at"], "datetime", "created_at 应为 DATETIME 类型")
+	})
+
+	t.Run("usage_stats 表字段", func(t *testing.T) {
+		var columns []struct {
+			Field string
+			Type  string
+		}
+		err := db.Raw("SHOW COLUMNS FROM usage_stats").Scan(&columns).Error
+		require.NoError(t, err)
+
+		columnMap := make(map[string]string)
+		for _, col := range columns {
+			columnMap[col.Field] = col.Type
+		}
+
+		assert.Contains(t, columnMap["id"], "int", "id 应为 INT 类型")
+		assert.Contains(t, columnMap["provider_id"], "varchar", "provider_id 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["model_name"], "varchar", "model_name 应为 VARCHAR 类型")
+		assert.Contains(t, columnMap["request_count"], "int", "request_count 应为 INT 类型")
+		assert.Contains(t, columnMap["date"], "date", "date 应为 DATE 类型")
+	})
+}
+
+func TestMigration_IndexesExist(t *testing.T) {
+	db := SetupMySQLTestDB(t)
+
+	t.Run("models 表索引", func(t *testing.T) {
+		var indexes []struct {
+			KeyName string
+		}
+		err := db.Raw("SHOW INDEX FROM models").Scan(&indexes).Error
+		require.NoError(t, err)
+
+		indexMap := make(map[string]bool)
+		for _, idx := range indexes {
+			indexMap[idx.KeyName] = true
+		}
+
+		assert.True(t, indexMap["idx_models_provider_id"], "idx_models_provider_id 索引应存在")
+		assert.True(t, indexMap["idx_models_model_name"], "idx_models_model_name 索引应存在")
+	})
+
+	t.Run("usage_stats 表索引", func(t *testing.T) {
+		var indexes []struct {
+			KeyName string
+		}
+		err := db.Raw("SHOW INDEX FROM usage_stats").Scan(&indexes).Error
+		require.NoError(t, err)
+
+		indexMap := make(map[string]bool)
+		for _, idx := range indexes {
+			indexMap[idx.KeyName] = true
+		}
+
+		assert.True(t, indexMap["idx_usage_stats_provider_model_date"], "idx_usage_stats_provider_model_date 索引应存在")
+	})
+}
diff --git a/backend/tests/mysql/testhelper.go b/backend/tests/mysql/testhelper.go
new file mode 100644
index 0000000..1ec7050
--- /dev/null
+++ b/backend/tests/mysql/testhelper.go
@@ -0,0 +1,160 @@
+//go:build mysql
+
+package mysql
+
+import (
+	"database/sql"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/pressly/goose/v3"
+	"github.com/stretchr/testify/require"
+	"gorm.io/driver/mysql"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+type MySQLTestConfig struct {
+	Host     string
+	Port     int
+	User     string
+	Password string
+	Database string
+}
+
+func getMySQLTestConfig() *MySQLTestConfig {
+	return &MySQLTestConfig{
+		Host:     getEnvOrDefault("NEX_TEST_MYSQL_HOST", "localhost"),
+		Port:     getEnvOrDefaultInt("NEX_TEST_MYSQL_PORT", 13306),
+		User:     getEnvOrDefault("NEX_TEST_MYSQL_USER", "nex_test"),
+		Password: getEnvOrDefault("NEX_TEST_MYSQL_PASSWORD", "testpass"),
+		Database: getEnvOrDefault("NEX_TEST_MYSQL_DATABASE", "nex_test"),
+	}
+}
+
+func getEnvOrDefault(key, defaultValue string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+	return defaultValue
+}
+
+func getEnvOrDefaultInt(key string, defaultValue int) int {
+	if value := os.Getenv(key); value != "" {
+		var intValue int
+		if _, err := fmt.Sscanf(value, "%d", &intValue); err == nil {
+			return intValue
+		}
+	}
+	return defaultValue
+}
+
+func SkipIfMySQLUnavailable(t *testing.T) {
+	t.Helper()
+
+	cfg := getMySQLTestConfig()
+	dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=true&loc=Local",
+		cfg.User, cfg.Password, cfg.Host, cfg.Port, cfg.Database)
+
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		t.Skipf("MySQL 不可用: %v", err)
+	}
+	defer db.Close()
+
+	if err := db.Ping(); err != nil {
+		t.Skipf("MySQL 不可用: %v", err)
+	}
+}
+
+func SetupMySQLTestDB(t *testing.T) *gorm.DB {
+	t.Helper()
+
+	SkipIfMySQLUnavailable(t)
+
+	cfg := getMySQLTestConfig()
+	dsn := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=true&loc=Local",
+		cfg.User, cfg.Password, cfg.Host, cfg.Port, cfg.Database)
+
+	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{
+		Logger: logger.Default.LogMode(logger.Silent),
+	})
+	require.NoError(t, err, "连接 MySQL 失败")
+
+	if err := runMigrations(db); err != nil {
+		require.NoError(t, err, "运行迁移失败")
+	}
+
+	if err := cleanupTables(db); err != nil {
+		require.NoError(t, err, "清理表数据失败")
+	}
+
+	sqlDB, err := db.DB()
+	require.NoError(t, err)
+	sqlDB.SetMaxIdleConns(10)
+	sqlDB.SetMaxOpenConns(100)
+	sqlDB.SetConnMaxLifetime(time.Hour)
+
+	t.Cleanup(func() {
+		time.Sleep(50 * time.Millisecond)
+		sqlDB, err := db.DB()
+		if err == nil {
+			sqlDB.Close()
+		}
+	})
+
+	return db
+}
+
+func cleanupTables(db *gorm.DB) error {
+	if err := db.Exec("SET FOREIGN_KEY_CHECKS = 0").Error; err != nil {
+		return err
+	}
+	if err := db.Exec("TRUNCATE TABLE usage_stats").Error; err != nil {
+		return err
+	}
+	if err := db.Exec("TRUNCATE TABLE models").Error; err != nil {
+		return err
+	}
+	if err := db.Exec("TRUNCATE TABLE providers").Error; err != nil {
+		return err
+	}
+	if err := db.Exec("SET FOREIGN_KEY_CHECKS = 1").Error; err != nil {
+		return err
+	}
+	return nil
+}
+
+func runMigrations(db *gorm.DB) error {
+	sqlDB, err := db.DB()
+	if err != nil {
+		return err
+	}
+
+	migrationsDir := getMigrationsDir()
+	if _, err := os.Stat(migrationsDir); os.IsNotExist(err) {
+		return fmt.Errorf("迁移目录不存在: %s", migrationsDir)
+	}
+
+	goose.SetDialect("mysql")
+	if err := goose.Up(sqlDB, migrationsDir); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func getMigrationsDir() string {
+	_, filename, _, ok := runtime.Caller(0)
+	if ok {
+		dir := filepath.Join(filepath.Dir(filename), "..", "..", "migrations", "mysql")
+		if abs, err := filepath.Abs(dir); err == nil {
+			return abs
+		}
+	}
+	return "./migrations/mysql"
+}
diff --git a/openspec/specs/config-management/spec.md b/openspec/specs/config-management/spec.md
index 006b5b2..3766110 100644
--- a/openspec/specs/config-management/spec.md
+++ b/openspec/specs/config-management/spec.md
@@ -77,6 +77,7 @@
 - **THEN** SHALL 支持 `required` 规则
 - **THEN** SHALL 支持 `min`、`max` 规则
 - **THEN** SHALL 支持 `oneof` 规则
+- **THEN** SHALL 支持 `required_if` 条件验证规则
 
 #### Scenario: 验证执行
 
@@ -85,6 +86,17 @@
 - **THEN** SHALL 返回验证错误
 - **THEN** SHALL NOT 启动应用（如果验证失败）
 
+#### Scenario: 数据库驱动条件验证
+
+- **WHEN** `database.driver` 为 `sqlite`
+- **THEN** SHALL 验证 `database.path` 必填
+- **THEN** SHALL NOT 要求 MySQL 字段（host/port/user/password/dbname）
+- **WHEN** `database.driver` 为 `mysql`
+- **THEN** SHALL 验证 `database.host` 必填
+- **THEN** SHALL 验证 `database.user` 必填
+- **THEN** SHALL 验证 `database.dbname` 必填
+- **THEN** SHALL NOT 要求 `database.path`
+
 ### Requirement: 配置结构定义
 
 系统 SHALL 定义清晰的配置结构。
@@ -98,7 +110,14 @@
 #### Scenario: Database 配置
 
 - **WHEN** 加载 database 配置
-- **THEN** SHALL 包含 path、max_idle_conns、max_open_conns、conn_max_lifetime 字段
+- **THEN** SHALL 包含 driver 字段（值为 `sqlite` 或 `mysql`，默认 `sqlite`）
+- **THEN** SHALL 包含 path 字段（SQLite 模式下的数据库文件路径）
+- **THEN** SHALL 包含 host 字段（MySQL 主机地址）
+- **THEN** SHALL 包含 port 字段（MySQL 端口，默认 3306）
+- **THEN** SHALL 包含 user 字段（MySQL 用户名）
+- **THEN** SHALL 包含 password 字段（MySQL 密码，选填）
+- **THEN** SHALL 包含 dbname 字段（MySQL 数据库名）
+- **THEN** SHALL 包含 max_idle_conns、max_open_conns、conn_max_lifetime 字段
 - **THEN** SHALL 使用合理的默认值
 
 #### Scenario: Log 配置
@@ -121,7 +140,13 @@
 #### Scenario: Database 默认值
 
 - **WHEN** 使用默认配置
+- **THEN** database.driver SHALL 为 `sqlite`
 - **THEN** database.path SHALL 为 `~/.nex/config.db`
+- **THEN** database.host SHALL 为空字符串
+- **THEN** database.port SHALL 为 3306
+- **THEN** database.user SHALL 为空字符串
+- **THEN** database.password SHALL 为空字符串
+- **THEN** database.dbname SHALL 为 `nex`
 - **THEN** database.max_idle_conns SHALL 为 10
 - **THEN** database.max_open_conns SHALL 为 100
 - **THEN** database.conn_max_lifetime SHALL 为 1h
@@ -248,18 +273,38 @@
 - **THEN** SHALL 在日志中记录覆盖信息
 - **THEN** SHALL 显示被覆盖的配置项名称
 
+### Requirement: 配置文件安全
+
+系统 SHALL 使用安全的文件权限保存配置文件。
+
+#### Scenario: 配置文件权限
+
+- **WHEN** 保存配置文件（`SaveConfig`）
+- **THEN** SHALL 使用 `0600` 权限写入文件（仅 owner 可读写）
+- **THEN** SHALL 防止其他用户读取配置中的 MySQL 密码等敏感信息
+
 ### Requirement: 配置摘要输出
 
 系统 SHALL 在启动时输出配置摘要。
 
-#### Scenario: 摘要内容
+#### Scenario: SQLite 模式摘要
 
-- **WHEN** 配置加载完成
+- **WHEN** `database.driver` 为 `sqlite`
 - **THEN** SHALL 打印关键配置项（端口、数据库路径、日志级别等）
 - **THEN** SHALL 打印配置文件路径
 - **THEN** SHALL 打印环境变量数量
 - **THEN** SHALL 打印 CLI 参数数量
 
+#### Scenario: MySQL 模式摘要
+
+- **WHEN** `database.driver` 为 `mysql`
+- **THEN** SHALL 打印关键配置项（端口、数据库类型、数据库地址、日志级别等）
+- **THEN** SHALL 打印数据库地址格式为 `{host}:{port}/{dbname}`
+- **THEN** SHALL 不打印密码
+- **THEN** SHALL 打印配置文件路径
+- **THEN** SHALL 打印环境变量数量
+- **THEN** SHALL 打印 CLI 参数数量
+
 #### Scenario: 摘要格式
 
 - **WHEN** 打印配置摘要
@@ -297,7 +342,7 @@
 - **WHEN** 使用服务器相关参数
 - **THEN** SHALL 支持 `--server-port`、`--server-read-timeout`、`--server-write-timeout`
 - **WHEN** 使用数据库相关参数
-- **THEN** SHALL 支持 `--database-path`、`--database-max-idle-conns`、`--database-max-open-conns`、`--database-conn-max-lifetime`
+- **THEN** SHALL 支持 `--database-driver`、`--database-path`、`--database-host`、`--database-port`、`--database-user`、`--database-password`、`--database-dbname`、`--database-max-idle-conns`、`--database-max-open-conns`、`--database-conn-max-lifetime`
 - **WHEN** 使用日志相关参数
 - **THEN** SHALL 支持 `--log-level`、`--log-path`、`--log-max-size`、`--log-max-backups`、`--log-max-age`、`--log-compress`
 
@@ -348,7 +393,7 @@
 - **WHEN** 设置服务器相关环境变量
 - **THEN** SHALL 支持 `NEX_SERVER_PORT`、`NEX_SERVER_READ_TIMEOUT`、`NEX_SERVER_WRITE_TIMEOUT`
 - **WHEN** 设置数据库相关环境变量
-- **THEN** SHALL 支持 `NEX_DATABASE_PATH`、`NEX_DATABASE_MAX_IDLE_CONNS`、`NEX_DATABASE_MAX_OPEN_CONNS`、`NEX_DATABASE_CONN_MAX_LIFETIME`
+- **THEN** SHALL 支持 `NEX_DATABASE_DRIVER`、`NEX_DATABASE_PATH`、`NEX_DATABASE_HOST`、`NEX_DATABASE_PORT`、`NEX_DATABASE_USER`、`NEX_DATABASE_PASSWORD`、`NEX_DATABASE_DBNAME`、`NEX_DATABASE_MAX_IDLE_CONNS`、`NEX_DATABASE_MAX_OPEN_CONNS`、`NEX_DATABASE_CONN_MAX_LIFETIME`
 - **WHEN** 设置日志相关环境变量
 - **THEN** SHALL 支持 `NEX_LOG_LEVEL`、`NEX_LOG_PATH`、`NEX_LOG_MAX_SIZE`、`NEX_LOG_MAX_BACKUPS`、`NEX_LOG_MAX_AGE`、`NEX_LOG_COMPRESS`
 
diff --git a/openspec/specs/database-migration/spec.md b/openspec/specs/database-migration/spec.md
index 733b4d1..ff13042 100644
--- a/openspec/specs/database-migration/spec.md
+++ b/openspec/specs/database-migration/spec.md
@@ -46,6 +46,14 @@
 - **THEN** SHALL 删除所有表和索引
 - **THEN** SHALL 按正确顺序删除（避免外键约束错误）
 
+#### Scenario: 按数据库方言拆分迁移目录
+
+- **WHEN** 组织迁移文件
+- **THEN** SHALL 将 SQLite 方言迁移文件存储在 `migrations/sqlite/` 目录
+- **THEN** SHALL 将 MySQL 方言迁移文件存储在 `migrations/mysql/` 目录
+- **THEN** SHALL 两个目录维护独立的版本号序列
+- **THEN** SHALL 两个目录的迁移文件内容在逻辑上一致（相同的表结构和约束），但使用各自方言的 DDL
+
 ### Requirement: models 表 schema 变更
 
 系统 SHALL 在初始迁移脚本中直接创建新的 models 表结构（服务未上线，无需考虑数据迁移，迁移脚本已合并为单个初始迁移文件）。
@@ -63,28 +71,37 @@
 
 #### Scenario: 迁移 up 命令
 
-- **WHEN** 执行 `make migrate-up`
+- **WHEN** 执行 `make backend-migrate-up`
 - **THEN** SHALL 执行所有待执行的迁移
+- **THEN** SHALL 使用 `DB_DRIVER` 变量选择方言目录（默认 `sqlite3`）
+- **THEN** SHALL 使用 `DB_DSN` 变量作为数据库连接串
 - **THEN** SHALL 显示迁移进度
 
 #### Scenario: 迁移 down 命令
 
-- **WHEN** 执行 `make migrate-down`
+- **WHEN** 执行 `make backend-migrate-down`
 - **THEN** SHALL 回滚最后一个迁移
+- **THEN** SHALL 使用 `DB_DRIVER` 和 `DB_DSN` 变量
 - **THEN** SHALL 显示回滚进度
 
 #### Scenario: 迁移状态命令
 
-- **WHEN** 执行 `make migrate-status`
+- **WHEN** 执行 `make backend-migrate-status`
 - **THEN** SHALL 显示当前迁移状态
 - **THEN** SHALL 显示已执行和待执行的迁移
 
 #### Scenario: 创建迁移命令
 
-- **WHEN** 执行 `make migrate-create name=<name>`
-- **THEN** SHALL 创建新的迁移文件模板
+- **WHEN** 执行 `make backend-migrate-create`
+- **THEN** SHALL 同时在 `migrations/sqlite/` 和 `migrations/mysql/` 两个目录创建新的迁移文件模板
 - **THEN** SHALL 使用递增的版本号
 
+#### Scenario: MySQL 迁移命令使用
+
+- **WHEN** 使用 MySQL 驱动执行迁移
+- **THEN** SHALL 设置 `DB_DRIVER=mysql`
+- **THEN** SHALL 设置 `DB_DSN` 为 MySQL 连接串（如 `user:pass@tcp(localhost:3306)/nex`）
+
 ### Requirement: 应用启动时迁移
 
 应用 SHALL 在启动时执行迁移。
@@ -92,6 +109,9 @@
 #### Scenario: 自动迁移
 
 - **WHEN** 应用启动
+- **THEN** SHALL 根据 `database.driver` 配置选择对应的迁移目录和 goose dialect
+- **THEN** SHALL 在 `driver=sqlite` 时使用 `migrations/sqlite/` 目录，goose dialect 为 `sqlite3`
+- **THEN** SHALL 在 `driver=mysql` 时使用 `migrations/mysql/` 目录，goose dialect 为 `mysql`
 - **THEN** SHALL 自动执行待执行的迁移
 - **THEN** SHALL 在迁移失败时拒绝启动
 - **THEN** SHALL 记录迁移日志
@@ -149,5 +169,5 @@
 #### Scenario: 迁移文件存储
 
 - **WHEN** 创建迁移文件
-- **THEN** SHALL 存储在 migrations/ 目录
+- **THEN** SHALL 按 SQL 方言存储在对应子目录（`migrations/sqlite/` 或 `migrations/mysql/`）
 - **THEN** SHALL 提交到版本控制系统
diff --git a/openspec/specs/mysql-driver/spec.md b/openspec/specs/mysql-driver/spec.md
new file mode 100644
index 0000000..dbcb979
--- /dev/null
+++ b/openspec/specs/mysql-driver/spec.md
@@ -0,0 +1,107 @@
+# MySQL Driver
+
+## Purpose
+
+支持 MySQL 作为可选数据库后端，通过配置选择 sqlite 或 mysql 驱动，提供 MySQL 连接管理、初始化和方言迁移文件。
+
+## Requirements
+
+### Requirement: MySQL 数据库驱动支持
+
+系统 SHALL 支持通过配置项 `database.driver` 选择 `sqlite` 或 `mysql` 数据库驱动，默认值为 `sqlite`。
+
+#### Scenario: 默认使用 SQLite 驱动
+
+- **WHEN** 配置中未指定 `database.driver`
+- **THEN** SHALL 使用 `sqlite` 作为数据库驱动
+- **THEN** SHALL 行为与现有逻辑完全一致
+
+#### Scenario: 配置 MySQL 驱动
+
+- **WHEN** 配置 `database.driver` 设置为 `mysql`
+- **THEN** SHALL 使用 MySQL 驱动连接远程数据库
+- **THEN** SHALL 使用 `gorm.io/driver/mysql` 打开连接
+- **THEN** SHALL 构建 DSN 格式为 `{user}:{password}@tcp({host}:{port})/{dbname}?charset=utf8mb4&parseTime=true&loc=Local`
+
+#### Scenario: driver 值不合法
+
+- **WHEN** 配置 `database.driver` 不是 `sqlite` 或 `mysql`
+- **THEN** SHALL 配置验证失败，拒绝启动
+
+### Requirement: MySQL 连接配置
+
+系统 SHALL 在 `DatabaseConfig` 中支持 MySQL 连接参数。
+
+#### Scenario: MySQL 连接参数字段
+
+- **WHEN** `database.driver` 为 `mysql`
+- **THEN** SHALL 读取 `host`（MySQL 主机地址，必填）
+- **THEN** SHALL 读取 `port`（MySQL 端口，默认 3306）
+- **THEN** SHALL 读取 `user`（MySQL 用户名，必填）
+- **THEN** SHALL 读取 `password`（MySQL 密码，选填）
+- **THEN** SHALL 读取 `dbname`（数据库名，必填）
+
+#### Scenario: SQLite 模式忽略 MySQL 参数
+
+- **WHEN** `database.driver` 为 `sqlite`
+- **THEN** SHALL 忽略 MySQL 相关配置字段（host/port/user/password/dbname）
+- **THEN** SHALL 仅使用 `path` 字段作为数据库文件路径
+
+#### Scenario: MySQL 模式忽略 SQLite 参数
+
+- **WHEN** `database.driver` 为 `mysql`
+- **THEN** SHALL 忽略 `path` 字段
+
+### Requirement: 数据库初始化公共包
+
+系统 SHALL 提供 `internal/database` 公共包，封装数据库初始化、迁移执行和连接关闭逻辑，供 `cmd/server` 和 `cmd/desktop` 共同调用。
+
+#### Scenario: 公共包 Init 函数
+
+- **WHEN** 调用 `database.Init(cfg, logger)`
+- **THEN** SHALL 根据 `cfg.Driver` 选择对应的 GORM 驱动打开连接
+- **THEN** SHALL 执行对应方言的 goose 迁移
+- **THEN** SHALL 配置连接池参数
+- **THEN** SHALL 在 `driver=sqlite` 时执行 `PRAGMA journal_mode=WAL`
+- **THEN** SHALL 在 `driver=mysql` 时跳过 SQLite 专有 PRAGMA
+- **THEN** SHALL 返回 `*gorm.DB` 实例
+
+#### Scenario: 公共包 Close 函数
+
+- **WHEN** 调用 `database.Close(db)`
+- **THEN** SHALL 获取底层 `sql.DB` 并关闭连接
+
+#### Scenario: 迁移目录选择
+
+- **WHEN** 执行迁移
+- **THEN** SHALL 在 `driver=sqlite` 时使用 `migrations/sqlite/` 目录，goose dialect 为 `sqlite3`
+- **THEN** SHALL 在 `driver=mysql` 时使用 `migrations/mysql/` 目录，goose dialect 为 `mysql`
+
+### Requirement: MySQL 方言迁移文件
+
+系统 SHALL 提供 MySQL 方言的初始迁移文件 `migrations/mysql/20260421000001_initial_schema.sql`。
+
+#### Scenario: providers 表
+
+- **WHEN** 执行 MySQL 初始迁移
+- **THEN** SHALL 创建 `providers` 表，字段：`id VARCHAR(36) PRIMARY KEY`、`name VARCHAR(255) NOT NULL`、`api_key VARCHAR(255) NOT NULL`、`base_url VARCHAR(255) NOT NULL`、`protocol VARCHAR(50) DEFAULT 'openai'`、`enabled BOOLEAN DEFAULT TRUE`、`created_at DATETIME(3)`、`updated_at DATETIME(3)`
+
+#### Scenario: models 表
+
+- **WHEN** 执行 MySQL 初始迁移
+- **THEN** SHALL 创建 `models` 表，字段：`id VARCHAR(36) PRIMARY KEY`、`provider_id VARCHAR(36) NOT NULL`、`model_name VARCHAR(255) NOT NULL`、`enabled BOOLEAN DEFAULT TRUE`、`created_at DATETIME(3)`
+- **THEN** SHALL 创建 `UNIQUE(provider_id, model_name)` 约束
+- **THEN** SHALL 创建 `FOREIGN KEY (provider_id) REFERENCES providers(id) ON DELETE CASCADE` 约束
+- **THEN** SHALL 创建 `idx_models_provider_id` 和 `idx_models_model_name` 索引
+
+#### Scenario: usage_stats 表
+
+- **WHEN** 执行 MySQL 初始迁移
+- **THEN** SHALL 创建 `usage_stats` 表，字段：`id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY`、`provider_id VARCHAR(36) NOT NULL`、`model_name VARCHAR(255) NOT NULL`、`request_count INT DEFAULT 0`、`date DATE NOT NULL`
+- **THEN** SHALL 创建 `UNIQUE(provider_id, model_name, date)` 约束
+- **THEN** SHALL 创建 `idx_usage_stats_provider_model_date` 复合索引
+
+#### Scenario: Down 迁移
+
+- **WHEN** 执行 MySQL down 迁移
+- **THEN** SHALL 按正确顺序删除索引和表（usage_stats → models → providers）
diff --git a/openspec/specs/mysql-testing/spec.md b/openspec/specs/mysql-testing/spec.md
new file mode 100644
index 0000000..5d6ecad
--- /dev/null
+++ b/openspec/specs/mysql-testing/spec.md
@@ -0,0 +1,104 @@
+# MySQL Testing
+
+## Purpose
+
+提供 MySQL 数据库专项测试能力，验证迁移正确性、外键约束、并发写入等数据库特定行为。
+
+## Requirements
+
+### Requirement: MySQL 测试环境可启动
+
+系统 SHALL 提供 Docker Compose 配置以启动 MySQL 8.0 测试环境。
+
+#### Scenario: 启动 MySQL 测试容器
+- **WHEN** 执行 `make test-mysql-up`
+- **THEN** 启动 MySQL 8.0 容器，端口 13306
+- **AND** 创建数据库 `nex_test`
+- **AND** 容器数据存储在内存盘（tmpfs）
+
+#### Scenario: 销毁 MySQL 测试容器
+- **WHEN** 执行 `make test-mysql-down`
+- **THEN** 停止并删除容器
+- **AND** 所有数据被销毁
+
+### Requirement: MySQL 测试可通过 build tag 控制
+
+MySQL 测试 SHALL 使用 `// +build mysql` build tag，默认不运行。
+
+#### Scenario: 默认测试不包含 MySQL 测试
+- **WHEN** 执行 `go test ./...`
+- **THEN** 不运行 `tests/mysql/` 下的测试
+
+#### Scenario: 启用 MySQL 测试
+- **WHEN** 执行 `go test -tags=mysql ./tests/mysql/...`
+- **THEN** 运行所有 MySQL 测试
+
+### Requirement: MySQL 迁移正确执行
+
+MySQL 测试 SHALL 验证迁移脚本在 MySQL 环境下正确执行。
+
+#### Scenario: 迁移创建所有表
+- **WHEN** 运行 MySQL 迁移
+- **THEN** 创建 `providers`、`models`、`usage_stats` 表
+- **AND** 字段类型符合 MySQL 迁移文件定义（VARCHAR、DATETIME(3)、BOOLEAN 等）
+- **AND** 索引 `idx_models_provider_id`、`idx_models_model_name`、`idx_usage_stats_provider_model_date` 创建成功
+
+#### Scenario: 迁移可重复执行
+- **WHEN** 在已迁移的数据库上再次运行迁移
+- **THEN** 不报错，数据库状态不变
+
+### Requirement: MySQL 外键约束生效
+
+MySQL 测试 SHALL 验证外键约束行为符合预期。
+
+#### Scenario: 外键约束阻止无效引用
+- **WHEN** 创建 model 时 `provider_id` 不存在
+- **THEN** 操作失败，返回外键约束错误
+
+#### Scenario: 级联删除生效
+- **WHEN** 删除 provider
+- **THEN** 该 provider 的所有 models 被级联删除
+
+### Requirement: MySQL UNIQUE 约束生效
+
+MySQL 测试 SHALL 验证 UNIQUE 约束行为符合预期。
+
+#### Scenario: models 表 UNIQUE 约束
+- **WHEN** 尝试创建相同 `(provider_id, model_name)` 组合的 model
+- **THEN** 操作失败，返回唯一约束错误
+
+#### Scenario: usage_stats 表 UNIQUE 约束
+- **WHEN** 尝试创建相同 `(provider_id, model_name, date)` 组合的 usage_stats
+- **THEN** 操作失败，返回唯一约束错误
+
+### Requirement: MySQL 并发写入正确
+
+MySQL 测试 SHALL 验证并发写入不丢失数据。
+
+#### Scenario: 并发记录 usage_stats
+- **WHEN** 10 个 goroutine 并发调用 `statsRepo.Record(providerID, modelName)`
+- **THEN** 最终 `request_count` 等于 10
+- **AND** 无数据丢失或重复
+
+#### Scenario: 并发创建相同 provider
+- **WHEN** 10 个 goroutine 并发创建相同 ID 的 provider
+- **THEN** 仅 1 个成功，其他 9 个失败
+
+#### Scenario: 并发创建相同 model
+- **WHEN** 10 个 goroutine 并发创建相同 `(provider_id, model_name)` 的 model
+- **THEN** 仅 1 个成功，其他 9 个失败
+
+### Requirement: MySQL 测试命令完整
+
+Makefile SHALL 提供完整的 MySQL 测试命令。
+
+#### Scenario: 完整测试流程
+- **WHEN** 执行 `make test-mysql`
+- **THEN** 启动 Docker MySQL
+- **AND** 等待 MySQL 就绪
+- **AND** 运行所有 MySQL 测试
+- **AND** 销毁容器
+
+#### Scenario: 快速测试（容器已运行）
+- **WHEN** 执行 `make test-mysql-quick`
+- **THEN** 直接运行测试，不管理容器生命周期
diff --git a/openspec/specs/usage-statistics/spec.md b/openspec/specs/usage-statistics/spec.md
index 7c5d4d0..abca1fa 100644
--- a/openspec/specs/usage-statistics/spec.md
+++ b/openspec/specs/usage-statistics/spec.md
@@ -93,7 +93,21 @@
 - **WHEN** 同时处理多个并发请求
 - **THEN** 网关 SHALL 使用原子操作正确增加每个请求的计数
 - **THEN** 不 SHALL 因并发写入而丢失统计
-- **THEN** SHALL 使用 StatsBuffer 的内存计数器
+- **THEN** SHALL 使用 upsert 操作保证原子性
+
+#### Scenario: 并发调用 Record 方法
+
+- **WHEN** 多个 goroutine 并发调用 StatsRepository.Record
+- **THEN** SHALL 使用 INSERT ... ON DUPLICATE KEY UPDATE (MySQL) 或 INSERT ... ON CONFLICT DO UPDATE (SQLite)
+- **THEN** SHALL 保证所有并发调用的计数都被正确累加
+- **THEN** 不 SHALL 因 UNIQUE 约束冲突而丢失数据
+
+#### Scenario: 并发调用 BatchUpdate 方法
+
+- **WHEN** 多个 goroutine 并发调用 StatsRepository.BatchUpdate
+- **THEN** SHALL 使用 upsert 操作保证原子性
+- **THEN** SHALL 正确累加所有 delta 值
+- **THEN** 不 SHALL 因并发写入而丢失统计
 
 ### Requirement: 使用 service 层处理业务逻辑
 
@@ -125,14 +139,14 @@ Service SHALL 通过 StatsRepository 访问数据。
 
 - **WHEN** StatsBuffer 刷新统计
 - **THEN** SHALL 调用 StatsRepository.BatchUpdate
-- **THEN** SHALL 使用事务更新或创建统计记录
+- **THEN** SHALL 使用 upsert 操作更新或创建统计记录
 - **THEN** SHALL 支持增量更新（request_count + delta）
 
-#### Scenario: 事务处理
+#### Scenario: upsert 操作
 
 - **WHEN** 记录统计
-- **THEN** SHALL 在 repository 层使用数据库事务
-- **THEN** SHALL 确保并发安全
+- **THEN** SHALL 在 repository 层使用 upsert 操作
+- **THEN** SHALL 保证原子性和并发安全
 
 ### Requirement: 统计查询优化
 
@@ -168,11 +182,18 @@ StatsRepository SHALL 新增 BatchUpdate 方法支持批量增量更新。
 #### Scenario: BatchUpdate 更新现有记录
 
 - **WHEN** 调用 BatchUpdate 且当日记录存在
-- **THEN** SHALL 使用事务更新 request_count = request_count + delta
+- **THEN** SHALL 使用 upsert 操作更新 request_count = request_count + delta
+- **THEN** SHALL 保证原子性，无竞态条件
 - **THEN** SHALL 不创建新记录
 
 #### Scenario: BatchUpdate 创建新记录
 
 - **WHEN** 调用 BatchUpdate 且当日记录不存在
 - **THEN** SHALL 创建新记录，request_count = delta
-- **THEN** SHALL 使用事务保证原子性
+- **THEN** SHALL 使用 upsert 操作保证原子性
+
+#### Scenario: BatchUpdate 并发安全
+
+- **WHEN** 多个 BatchUpdate 调用同时执行
+- **THEN** SHALL 保证所有 delta 都被正确累加
+- **THEN** SHALL 不因并发冲突而丢失数据