diff --git a/backend/internal/bootstrap/database.go b/backend/internal/bootstrap/database.go
new file mode 100644
index 0000000..f118d98
--- /dev/null
+++ b/backend/internal/bootstrap/database.go
@@ -0,0 +1,395 @@
+package bootstrap
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"net"
+	"net/url"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+	"unicode"
+
+	"github.com/go-sql-driver/mysql"
+
+	"git.pcux.cn/xuans/Scert/backend/internal/config"
+	"git.pcux.cn/xuans/Scert/backend/internal/database"
+)
+
+const (
+	databaseVerificationLifetime         = 15 * time.Minute
+	databaseVerificationCapacity         = 128
+	databaseVerificationInFlightCapacity = 8
+	databaseVerificationCleanupTimeout   = 10 * time.Second
+)
+
+var databaseNamePattern = regexp.MustCompile(`^[A-Za-z0-9_.-]{1,128}$`)
+
+type DatabaseSecretStore interface {
+	database.CredentialReader
+	Put(context.Context, string, map[string]string) error
+	Delete(context.Context, string) error
+}
+
+type DatabaseInput struct {
+	Driver          string `json:"driver"`
+	Host            string `json:"host"`
+	Port            int    `json:"port"`
+	Database        string `json:"database"`
+	Username        string `json:"username"`
+	Password        string `json:"password"`
+	TLSMode         string `json:"tls_mode"`
+	RootCertificate string `json:"root_certificate"`
+}
+
+type DatabaseVerificationResult struct {
+	Config            config.DatabaseConfig `json:"database"`
+	CredentialRef     string                `json:"credential_ref,omitempty"`
+	VerificationToken string                `json:"verification_token"`
+	ExpiresAt         time.Time             `json:"expires_at"`
+}
+
+type databaseVerificationSession struct {
+	Config        config.DatabaseConfig
+	CredentialRef string
+	ExpiresAt     time.Time
+}
+
+type DatabaseVerificationManager struct {
+	mu       sync.Mutex
+	base     config.Config
+	store    DatabaseSecretStore
+	verify   func(context.Context, config.DatabaseConfig) error
+	now      func() time.Time
+	sessions map[string]databaseVerificationSession
+	inFlight int
+}
+
+func NewDatabaseVerificationManager(base config.Config, store DatabaseSecretStore) *DatabaseVerificationManager {
+	return &DatabaseVerificationManager{
+		base: base, store: store, verify: database.VerifyWritable, now: time.Now,
+		sessions: make(map[string]databaseVerificationSession),
+	}
+}
+
+func (m *DatabaseVerificationManager) Verify(ctx context.Context, input DatabaseInput) (DatabaseVerificationResult, error) {
+	if m == nil || m.verify == nil || m.store == nil {
+		return DatabaseVerificationResult{}, errors.New("数据库验证服务尚未初始化")
+	}
+	if err := m.reserve(); err != nil {
+		return DatabaseVerificationResult{}, err
+	}
+	released := false
+	defer func() {
+		if !released {
+			m.release()
+		}
+	}()
+
+	persisted, credentials, err := buildDatabaseConfig(m.base, input)
+	if err != nil {
+		return DatabaseVerificationResult{}, err
+	}
+	credentialRef := ""
+	if len(credentials) > 0 {
+		credentialRef, err = database.NewCredentialReference()
+		if err != nil {
+			return DatabaseVerificationResult{}, err
+		}
+		persisted.CredentialRef = credentialRef
+		if err := m.store.Put(ctx, credentialRef, credentials); err != nil {
+			return DatabaseVerificationResult{}, fmt.Errorf("加密保存数据库凭据失败：%w", err)
+		}
+	}
+	keepCredential := false
+	defer func() {
+		if !keepCredential && credentialRef != "" {
+			_ = m.deleteCredential(credentialRef)
+		}
+	}()
+
+	resolved, err := database.ResolveConfig(ctx, persisted, m.store)
+	if err != nil {
+		return DatabaseVerificationResult{}, err
+	}
+	if err := m.verify(ctx, resolved); err != nil {
+		return DatabaseVerificationResult{}, fmt.Errorf("数据库连接或写权限验证失败：%w", err)
+	}
+	token, err := randomToken(32)
+	if err != nil {
+		return DatabaseVerificationResult{}, fmt.Errorf("生成数据库验证令牌失败：%w", err)
+	}
+	expiresAt := m.now().UTC().Add(databaseVerificationLifetime)
+	m.mu.Lock()
+	expired := m.clearExpiredLocked(m.now().UTC())
+	m.sessions[token] = databaseVerificationSession{
+		Config: persisted, CredentialRef: credentialRef, ExpiresAt: expiresAt,
+	}
+	m.inFlight--
+	released = true
+	m.mu.Unlock()
+	m.deleteCredentials(expired)
+	keepCredential = true
+	return DatabaseVerificationResult{
+		Config: persisted, CredentialRef: credentialRef,
+		VerificationToken: token, ExpiresAt: expiresAt,
+	}, nil
+}
+
+func (m *DatabaseVerificationManager) Check(token, credentialRef string) (config.DatabaseConfig, error) {
+	return m.session(token, credentialRef, false)
+}
+
+func (m *DatabaseVerificationManager) Consume(token, credentialRef string) (config.DatabaseConfig, error) {
+	return m.session(token, credentialRef, true)
+}
+
+func (m *DatabaseVerificationManager) session(token, credentialRef string, consume bool) (config.DatabaseConfig, error) {
+	if m == nil {
+		return config.DatabaseConfig{}, errors.New("数据库验证服务尚未初始化")
+	}
+	token = strings.TrimSpace(token)
+	if token == "" {
+		return config.DatabaseConfig{}, errors.New("必须先完成数据库连接和写权限测试")
+	}
+	now := m.now().UTC()
+	m.mu.Lock()
+	expired := m.clearExpiredLocked(now)
+	session, ok := m.sessions[token]
+	if !ok {
+		m.mu.Unlock()
+		m.deleteCredentials(expired)
+		return config.DatabaseConfig{}, errors.New("数据库验证令牌无效或已经过期，请重新测试")
+	}
+	if session.CredentialRef != strings.TrimSpace(credentialRef) {
+		m.mu.Unlock()
+		m.deleteCredentials(expired)
+		return config.DatabaseConfig{}, errors.New("数据库验证结果与当前配置不匹配，请重新测试")
+	}
+	if consume {
+		delete(m.sessions, token)
+	}
+	m.mu.Unlock()
+	m.deleteCredentials(expired)
+	return session.Config, nil
+}
+
+func (m *DatabaseVerificationManager) DiscardAll() {
+	if m == nil {
+		return
+	}
+	m.mu.Lock()
+	references := make([]string, 0, len(m.sessions))
+	for token, session := range m.sessions {
+		delete(m.sessions, token)
+		if session.CredentialRef != "" {
+			references = append(references, session.CredentialRef)
+		}
+	}
+	m.mu.Unlock()
+	m.deleteCredentials(references)
+}
+
+func (m *DatabaseVerificationManager) reserve() error {
+	now := m.now().UTC()
+	m.mu.Lock()
+	expired := m.clearExpiredLocked(now)
+	if m.inFlight >= databaseVerificationInFlightCapacity {
+		m.mu.Unlock()
+		m.deleteCredentials(expired)
+		return errors.New("数据库验证请求过多，请稍后重试")
+	}
+	if len(m.sessions)+m.inFlight >= databaseVerificationCapacity {
+		m.mu.Unlock()
+		m.deleteCredentials(expired)
+		return errors.New("数据库验证令牌数量已达上限，请等待现有验证完成或过期后重试")
+	}
+	m.inFlight++
+	m.mu.Unlock()
+	m.deleteCredentials(expired)
+	return nil
+}
+
+func (m *DatabaseVerificationManager) release() {
+	m.mu.Lock()
+	if m.inFlight > 0 {
+		m.inFlight--
+	}
+	m.mu.Unlock()
+}
+
+func (m *DatabaseVerificationManager) clearExpiredLocked(now time.Time) []string {
+	references := make([]string, 0)
+	for token, session := range m.sessions {
+		if session.ExpiresAt.After(now) {
+			continue
+		}
+		delete(m.sessions, token)
+		if session.CredentialRef != "" {
+			references = append(references, session.CredentialRef)
+		}
+	}
+	return references
+}
+
+func (m *DatabaseVerificationManager) deleteCredentials(references []string) {
+	for _, reference := range references {
+		_ = m.deleteCredential(reference)
+	}
+}
+
+func (m *DatabaseVerificationManager) deleteCredential(reference string) error {
+	if strings.TrimSpace(reference) == "" || m == nil || m.store == nil {
+		return nil
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), databaseVerificationCleanupTimeout)
+	defer cancel()
+	return m.store.Delete(ctx, reference)
+}
+
+func buildDatabaseConfig(base config.Config, input DatabaseInput) (config.DatabaseConfig, map[string]string, error) {
+	driver := strings.ToLower(strings.TrimSpace(input.Driver))
+	result := base.Database
+	result.Driver = driver
+	result.CredentialRef = ""
+	if result.MaxOpenConns < 1 {
+		result.MaxOpenConns = 4
+	}
+	if result.MaxIdleConns < 0 || result.MaxIdleConns > result.MaxOpenConns {
+		result.MaxIdleConns = 2
+	}
+	if result.ConnMaxLifetimeMins < 0 {
+		result.ConnMaxLifetimeMins = 30
+	}
+	switch driver {
+	case "sqlite":
+		if strings.TrimSpace(input.Host) != "" || input.Port != 0 || strings.TrimSpace(input.Database) != "" ||
+			strings.TrimSpace(input.Username) != "" || input.Password != "" || strings.TrimSpace(input.RootCertificate) != "" {
+			return config.DatabaseConfig{}, nil, errors.New("SQLite 使用系统管理的数据文件，不接受外部连接参数")
+		}
+		result.DSN = filepath.Join(base.Paths.Data, "scert.db")
+		return result, nil, database.ValidateConfig(result)
+	case "mysql", "postgres":
+		// 继续进行外部数据库结构化字段校验。
+	default:
+		return config.DatabaseConfig{}, nil, fmt.Errorf("数据库类型无效：%s", input.Driver)
+	}
+
+	host, err := normalizeDatabaseHost(input.Host)
+	if err != nil {
+		return config.DatabaseConfig{}, nil, err
+	}
+	port := input.Port
+	if port == 0 && driver == "mysql" {
+		port = 3306
+	}
+	if port == 0 && driver == "postgres" {
+		port = 5432
+	}
+	if port < 1 || port > 65535 {
+		return config.DatabaseConfig{}, nil, fmt.Errorf("数据库端口无效：%d", port)
+	}
+	databaseName := strings.TrimSpace(input.Database)
+	if !databaseNamePattern.MatchString(databaseName) {
+		return config.DatabaseConfig{}, nil, errors.New("数据库名称格式无效")
+	}
+	username := strings.TrimSpace(input.Username)
+	if username == "" || len(username) > 128 || containsControl(username) {
+		return config.DatabaseConfig{}, nil, errors.New("数据库用户名格式无效")
+	}
+	if input.Password == "" || len(input.Password) > 4096 || containsControl(input.Password) {
+		return config.DatabaseConfig{}, nil, errors.New("数据库密码不能为空且不能包含控制字符")
+	}
+
+	tlsMode := strings.ToLower(strings.TrimSpace(input.TLSMode))
+	if driver == "mysql" {
+		if tlsMode == "" {
+			tlsMode = "true"
+		}
+		if tlsMode != "true" {
+			return config.DatabaseConfig{}, nil, errors.New("MySQL 初始化连接必须启用证书和主机名校验，tls_mode 只能为 true")
+		}
+		if strings.TrimSpace(input.RootCertificate) != "" {
+			return config.DatabaseConfig{}, nil, errors.New("当前 MySQL 初始化仅支持系统信任库，不接受自定义根证书路径")
+		}
+		mysqlConfig := mysql.NewConfig()
+		mysqlConfig.Net = "tcp"
+		mysqlConfig.Addr = net.JoinHostPort(host, strconv.Itoa(port))
+		mysqlConfig.DBName = databaseName
+		mysqlConfig.TLSConfig = "true"
+		mysqlConfig.ParseTime = true
+		mysqlConfig.Loc = time.UTC
+		mysqlConfig.Params = map[string]string{"charset": "utf8mb4"}
+		result.DSN = mysqlConfig.FormatDSN()
+	} else {
+		if tlsMode != "" && tlsMode != "verify-full" {
+			return config.DatabaseConfig{}, nil, errors.New("PostgreSQL 初始化连接必须使用 sslmode=verify-full")
+		}
+		query := url.Values{"sslmode": []string{"verify-full"}}
+		if root := strings.TrimSpace(input.RootCertificate); root != "" {
+			if !filepath.IsAbs(root) {
+				return config.DatabaseConfig{}, nil, errors.New("PostgreSQL 根证书路径必须是绝对路径")
+			}
+			query.Set("sslrootcert", filepath.Clean(root))
+		}
+		result.DSN = (&url.URL{
+			Scheme: "postgres", Host: net.JoinHostPort(host, strconv.Itoa(port)),
+			Path: "/" + databaseName, RawQuery: query.Encode(),
+		}).String()
+	}
+	credentials := map[string]string{"username": username, "password": input.Password}
+	credentialRef, err := database.NewCredentialReference()
+	if err != nil {
+		return config.DatabaseConfig{}, nil, err
+	}
+	result.CredentialRef = credentialRef
+	if err := database.ValidateConfig(result); err != nil {
+		return config.DatabaseConfig{}, nil, err
+	}
+	result.CredentialRef = ""
+	return result, credentials, nil
+}
+
+func normalizeDatabaseHost(value string) (string, error) {
+	host := strings.Trim(strings.TrimSpace(value), "[]")
+	if host == "" || len(host) > 253 || containsControl(host) || strings.ContainsAny(host, `/\\@?#`) {
+		return "", errors.New("数据库主机格式无效")
+	}
+	if net.ParseIP(host) != nil {
+		return host, nil
+	}
+	for _, label := range strings.Split(host, ".") {
+		if label == "" || len(label) > 63 || strings.HasPrefix(label, "-") || strings.HasSuffix(label, "-") {
+			return "", errors.New("数据库主机格式无效")
+		}
+		for _, char := range label {
+			if (char < 'a' || char > 'z') && (char < 'A' || char > 'Z') && (char < '0' || char > '9') && char != '-' && char != '_' {
+				return "", errors.New("数据库主机格式无效")
+			}
+		}
+	}
+	return host, nil
+}
+
+func containsControl(value string) bool {
+	for _, char := range value {
+		if unicode.IsControl(char) {
+			return true
+		}
+	}
+	return false
+}
+
+func randomToken(size int) (string, error) {
+	buffer := make([]byte, size)
+	if _, err := rand.Read(buffer); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(buffer), nil
+}
diff --git a/backend/internal/bootstrap/database_test.go b/backend/internal/bootstrap/database_test.go
new file mode 100644
index 0000000..c1a59ac
--- /dev/null
+++ b/backend/internal/bootstrap/database_test.go
@@ -0,0 +1,159 @@
+package bootstrap
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"git.pcux.cn/xuans/Scert/backend/internal/config"
+)
+
+type memoryDatabaseStore struct {
+	mu     sync.Mutex
+	values map[string]map[string]string
+}
+
+func (s *memoryDatabaseStore) Put(_ context.Context, reference string, value map[string]string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.values == nil {
+		s.values = make(map[string]map[string]string)
+	}
+	s.values[reference] = map[string]string{"username": value["username"], "password": value["password"]}
+	return nil
+}
+
+func (s *memoryDatabaseStore) Get(_ context.Context, reference string) (map[string]string, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.values[reference], nil
+}
+
+func (s *memoryDatabaseStore) Delete(_ context.Context, reference string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	delete(s.values, reference)
+	return nil
+}
+
+func TestBuildDatabaseConfigSupportsThreeStorageModesWithoutPersistingCredentials(t *testing.T) {
+	base := config.Default(t.TempDir())
+	base.Paths.Data = filepath.Join(t.TempDir(), "data")
+	tests := []struct {
+		name  string
+		input DatabaseInput
+	}{
+		{name: "SQLite", input: DatabaseInput{Driver: "sqlite"}},
+		{name: "MySQL", input: DatabaseInput{Driver: "mysql", Host: "db.example.test", Database: "scert", Username: "scert_user", Password: "mysql-secret", TLSMode: "true"}},
+		{name: "PostgreSQL", input: DatabaseInput{Driver: "postgres", Host: "db.example.test", Database: "scert", Username: "scert_user", Password: "postgres-secret", TLSMode: "verify-full"}},
+	}
+	for _, item := range tests {
+		t.Run(item.name, func(t *testing.T) {
+			persisted, credentials, err := buildDatabaseConfig(base, item.input)
+			if err != nil {
+				t.Fatalf("构造数据库配置失败：%v", err)
+			}
+			if (item.input.Username != "" && strings.Contains(persisted.DSN, item.input.Username)) ||
+				(item.input.Password != "" && strings.Contains(persisted.DSN, item.input.Password)) {
+				t.Fatalf("持久化数据库配置泄露账号或密码：%s", persisted.DSN)
+			}
+			if item.input.Driver == "sqlite" {
+				if len(credentials) != 0 || persisted.DSN != filepath.Join(base.Paths.Data, "scert.db") {
+					t.Fatalf("SQLite 配置不正确：%+v credentials=%v", persisted, credentials)
+				}
+				return
+			}
+			if credentials["username"] != item.input.Username || credentials["password"] != item.input.Password {
+				t.Fatal("外部数据库凭据未单独返回")
+			}
+		})
+	}
+}
+
+func TestDatabaseVerificationStoresCredentialsAndConsumesTokenOnce(t *testing.T) {
+	base := config.Default(t.TempDir())
+	store := &memoryDatabaseStore{}
+	manager := NewDatabaseVerificationManager(base, store)
+	manager.verify = func(_ context.Context, runtime config.DatabaseConfig) error {
+		if !strings.Contains(runtime.DSN, "database-password") {
+			t.Fatalf("运行时连接信息未注入内存密码：%s", runtime.DSN)
+		}
+		return nil
+	}
+	result, err := manager.Verify(t.Context(), DatabaseInput{
+		Driver: "mysql", Host: "db.example.test", Database: "scert",
+		Username: "scert_user", Password: "database-password", TLSMode: "true",
+	})
+	if err != nil {
+		t.Fatalf("数据库验证失败：%v", err)
+	}
+	if result.CredentialRef == "" || result.VerificationToken == "" {
+		t.Fatal("数据库验证结果缺少加密凭据引用或令牌")
+	}
+	if strings.Contains(result.Config.DSN, "scert_user") || strings.Contains(result.Config.DSN, "database-password") {
+		t.Fatalf("数据库验证响应泄露凭据：%+v", result.Config)
+	}
+	consumed, err := manager.Consume(result.VerificationToken, result.CredentialRef)
+	if err != nil || consumed.CredentialRef != result.CredentialRef {
+		t.Fatalf("消费数据库验证令牌失败：%v config=%+v", err, consumed)
+	}
+	if _, err := manager.Consume(result.VerificationToken, result.CredentialRef); err == nil {
+		t.Fatal("数据库验证令牌被重复消费")
+	}
+	store.mu.Lock()
+	_, retained := store.values[result.CredentialRef]
+	store.mu.Unlock()
+	if !retained {
+		t.Fatal("已消费的正式数据库凭据不应被验证令牌管理器删除")
+	}
+}
+
+func TestDatabaseVerificationFailureAndExpiryDeleteTemporaryCredentials(t *testing.T) {
+	base := config.Default(t.TempDir())
+	store := &memoryDatabaseStore{}
+	manager := NewDatabaseVerificationManager(base, store)
+	manager.verify = func(context.Context, config.DatabaseConfig) error { return context.DeadlineExceeded }
+	if _, err := manager.Verify(t.Context(), DatabaseInput{
+		Driver: "postgres", Host: "db.example.test", Database: "scert",
+		Username: "scert_user", Password: "database-password", TLSMode: "verify-full",
+	}); err == nil {
+		t.Fatal("数据库验证失败未返回错误")
+	}
+	store.mu.Lock()
+	count := len(store.values)
+	store.mu.Unlock()
+	if count != 0 {
+		t.Fatalf("失败的数据库验证遗留临时凭据：%d", count)
+	}
+
+	manager.verify = func(context.Context, config.DatabaseConfig) error { return nil }
+	now := time.Now().UTC()
+	manager.now = func() time.Time { return now }
+	result, err := manager.Verify(t.Context(), DatabaseInput{
+		Driver: "mysql", Host: "db.example.test", Database: "scert",
+		Username: "scert_user", Password: "database-password", TLSMode: "true",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	manager.now = func() time.Time { return now.Add(databaseVerificationLifetime + time.Second) }
+	if _, err := manager.Check(result.VerificationToken, result.CredentialRef); err == nil {
+		t.Fatal("过期数据库验证令牌未被拒绝")
+	}
+	store.mu.Lock()
+	_, exists := store.values[result.CredentialRef]
+	store.mu.Unlock()
+	if exists {
+		t.Fatal("过期数据库验证令牌的临时凭据未被删除")
+	}
+}
+
+func TestSQLiteRejectsUserControlledPathAndExternalFields(t *testing.T) {
+	base := config.Default(t.TempDir())
+	if _, _, err := buildDatabaseConfig(base, DatabaseInput{Driver: "sqlite", Database: "other.db"}); err == nil {
+		t.Fatal("SQLite 用户自定义路径未被拒绝")
+	}
+}
diff --git a/backend/internal/database/credentials.go b/backend/internal/database/credentials.go
index 7876136..03d5625 100644
--- a/backend/internal/database/credentials.go
+++ b/backend/internal/database/credentials.go
@@ -57,17 +57,34 @@ func ValidateConfig(cfg config.DatabaseConfig) error {
 		if err != nil {
 			return fmt.Errorf("解析 MySQL 连接信息失败：%w", err)
 		}
-		if strings.TrimSpace(parsed.User) == "" {
-			return fmt.Errorf("MySQL 连接信息必须包含用户名")
+		if strings.TrimSpace(parsed.User) != "" {
+			return fmt.Errorf("MySQL 用户名只能保存到加密凭据中")
 		}
 		return nil
 	}
-	if _, err := normalizePostgresDSN(dsn); err != nil {
+	if err := validatePersistedPostgresDSN(dsn); err != nil {
 		return err
 	}
 	return nil
 }
 
+func validatePersistedPostgresDSN(dsn string) error {
+	parsed, err := url.Parse(strings.TrimSpace(dsn))
+	if err != nil || (parsed.Scheme != "postgres" && parsed.Scheme != "postgresql") {
+		return fmt.Errorf("PostgreSQL 数据库连接信息必须使用不含账号密码的 postgres:// URL")
+	}
+	if strings.TrimSpace(parsed.Hostname()) == "" || strings.Trim(strings.TrimSpace(parsed.Path), "/") == "" {
+		return fmt.Errorf("PostgreSQL 连接信息必须包含主机和数据库")
+	}
+	if parsed.User != nil {
+		return fmt.Errorf("PostgreSQL 用户名和密码只能保存到加密凭据中")
+	}
+	if postgresSSLMode(dsn) != "verify-full" {
+		return fmt.Errorf("PostgreSQL 连接必须使用 sslmode=verify-full")
+	}
+	return nil
+}
+
 // ResolveConfig 从凭据存储中读取外部数据库账号，在内存中构造连接配置。
 // 返回值绝不能保存或记录到日志。
 func ResolveConfig(ctx context.Context, cfg config.DatabaseConfig, reader CredentialReader) (config.DatabaseConfig, error) {
diff --git a/backend/internal/database/credentials_test.go b/backend/internal/database/credentials_test.go
index be0a377..f05c4f4 100644
--- a/backend/internal/database/credentials_test.go
+++ b/backend/internal/database/credentials_test.go
@@ -46,12 +46,12 @@ func TestResolveConfigBuildsRuntimeDSNWithoutChangingPersistedConfig(t *testing.
 	}{
 		{
 			name:       "MySQL",
-			cfg:        config.DatabaseConfig{Driver: "mysql", DSN: "user@tcp(db.example.test:3306)/scert?charset=utf8mb4", CredentialRef: "secret://database/mysql"},
+			cfg:        config.DatabaseConfig{Driver: "mysql", DSN: "tcp(db.example.test:3306)/scert?charset=utf8mb4&tls=true", CredentialRef: "secret://database/mysql"},
 			wantSecret: "mysql-password",
 		},
 		{
 			name:       "PostgreSQL",
-			cfg:        config.DatabaseConfig{Driver: "postgres", DSN: "postgres://user@db.example.test:5432/scert?sslmode=verify-full", CredentialRef: "secret://database/postgres"},
+			cfg:        config.DatabaseConfig{Driver: "postgres", DSN: "postgres://db.example.test:5432/scert?sslmode=verify-full", CredentialRef: "secret://database/postgres"},
 			wantSecret: "postgres-password",
 		},
 	}
@@ -74,6 +74,17 @@ func TestResolveConfigBuildsRuntimeDSNWithoutChangingPersistedConfig(t *testing.
 	}
 }
 
+func TestValidateConfigKeepsExternalDatabaseUsernameOutOfPersistedDSN(t *testing.T) {
+	for _, cfg := range []config.DatabaseConfig{
+		{Driver: "mysql", DSN: "user@tcp(db.example.test:3306)/scert?tls=true", CredentialRef: "secret://database/mysql"},
+		{Driver: "postgres", DSN: "postgres://user@db.example.test:5432/scert?sslmode=verify-full", CredentialRef: "secret://database/postgres"},
+	} {
+		if err := ValidateConfig(cfg); err == nil {
+			t.Fatalf("持久化配置中的数据库用户名未被拒绝：%s", cfg.Driver)
+		}
+	}
+}
+
 func TestVerifyWritableSQLiteCleansTemporaryTable(t *testing.T) {
 	cfg := config.Default(t.TempDir()).Database
 	if err := VerifyWritable(t.Context(), cfg); err != nil {