实现数据库级联删除

internal/repository/media_repo.go

@@ -12,15 +12,11 @@ func NewMediaRepository(db *sql.DB) *MediaRepository {
 
 func (r *MediaRepository) Get(id int) (MediaFile, error) {
 	var m MediaFile
-	rows, err := r.db.Query("SELECT id, path, library_id FROM media_files WHERE id = ?", id)
+	err := r.db.QueryRow("SELECT id, path, library_id FROM media_files WHERE id = ?", id).Scan(
+		&m.ID, &m.Path, &m.LibraryID,
+	)
 	if err != nil {
 		return MediaFile{}, err
 	}
-	defer rows.Close()
-	if rows.Next() {
-		if err := rows.Scan(&m.ID, &m.Path, &m.LibraryID); err != nil {
-			return MediaFile{}, err
-		}
-	}
 	return m, nil
 }