实现数据库级联删除

internal/repository/song_repo.go

@@ -55,13 +55,11 @@ func (r *SongRepository) GetAllWithDetails() ([]SongDetail, error) {
 
 func (r *SongRepository) Get(id int) (Song, error) {
 	var song Song
-	rows, err := r.db.Query("SELECT id, title, artist_id, album_id, duration, media_file_id FROM songs WHERE id = ?", id)
+	err := r.db.QueryRow("SELECT id, title, artist_id, album_id, duration, media_file_id FROM songs WHERE id = ?", id).Scan(
+		&song.ID, &song.Title, &song.ArtistID, &song.AlbumID, &song.Duration, &song.MediaFileID,
+	)
 	if err != nil {
 		return Song{}, err
 	}
-	defer rows.Close()
-	if rows.Next() {
-		rows.Scan(&song.ID, &song.Title, &song.ArtistID, &song.AlbumID, &song.Duration, &song.MediaFileID)
-	}
 	return song, nil
 }