diff --git a/internal/storage/models.go b/internal/storage/models.go
index 25e7549..b87eef6 100644
--- a/internal/storage/models.go
+++ b/internal/storage/models.go
@@ -48,9 +48,9 @@ func (BucketStats) TableName() string {
 // BucketMonthlyStats 存储桶月度统计信息模型
 type BucketMonthlyStats struct {
 	ID              uint      `gorm:"primaryKey" json:"id"`
-	BucketName      string    `gorm:"index:idx_bucket_month;size:255;not null" json:"bucket_name"`
-	Year            int       `gorm:"index:idx_bucket_month;not null" json:"year"`
-	Month           int       `gorm:"index:idx_bucket_month;not null" json:"month"`
+	BucketName      string    `gorm:"uniqueIndex:idx_bucket_month;size:255;not null" json:"bucket_name"`
+	Year            int       `gorm:"uniqueIndex:idx_bucket_month;not null" json:"year"`
+	Month           int       `gorm:"uniqueIndex:idx_bucket_month;not null" json:"month"`
 	OperationCountA int64     `gorm:"not null;default:0" json:"operation_count_a"`
 	OperationCountB int64     `gorm:"not null;default:0" json:"operation_count_b"`
 	CreatedAt       time.Time `json:"created_at"`