插入新的一对多的数据插入表与SQLAlchemy的ORM

Question

我试图将行插入，它有三个表的数据库：

• 艺术家
• 歌曲
• 媒体（如YouTube的视频）

艺术家与歌曲和歌曲有一对多的关系，与媒体有一对多的关系。当艺术家，歌曲和媒体是新的并需要添加到数据库的情况下，我会陷入困境。

我想我可以添加艺术家，提交它，然后检索艺术家对象，然后用艺术家对象添加的歌曲，运用同样的想法歌曲>媒体。但是，这似乎并不是最有效的方法。

我尝试添加的每个对象首次然后commiting底：

new_artist = models.Artist(
    name = artist_name, 
    ) 
db.session.add(artist) 

new_song = models.Song(
    name = song_name, 
    artist = artist, 
    ) 
db.session.add(song) 

new_media = models.Media(
    song = song, 
    media_id = media_id, 
    user=user 
    ) 
db.session.add(media) 
db.session.commit() 

但我发现了这个错误：

Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
    File "/path/python2.7/site-packages/sqlalchemy/orm/scoping.py", line 114, in do 
    return getattr(self.registry(), name)(*args, **kwargs) 
    File "/path/python2.7/site-packages/sqlalchemy/orm/session.py", line 703, in commit 
    self.transaction.commit() 
    File "/path/python2.7/site-packages/sqlalchemy/orm/session.py", line 361, in commit 
    self._prepare_impl() 
    File "/path/python2.7/site-packages/sqlalchemy/orm/session.py", line 340, in _prepare_impl 
    self.session.flush() 
    File "/path/python2.7/site-packages/sqlalchemy/orm/session.py", line 1718, in flush 
    self._flush(objects) 
    File "/path/python2.7/site-packages/sqlalchemy/orm/session.py", line 1789, in _flush 
    flush_context.execute() 
    File "/path/python2.7/site-packages/sqlalchemy/orm/unitofwork.py", line 331, in execute 
    rec.execute(self) 
    File "/path/python2.7/site-packages/sqlalchemy/orm/unitofwork.py", line 475, in execute 
    uow 
    File "/path/python2.7/site-packages/sqlalchemy/orm/persistence.py", line 64, in save_obj 
    table, insert) 
    File "/path/python2.7/site-packages/sqlalchemy/orm/persistence.py", line 558, in _emit_insert_statements 
    execute(statement, params) 
    File "/path/python2.7/site-packages/sqlalchemy/engine/base.py", line 1449, in execute 
    params) 
    File "/path/python2.7/site-packages/sqlalchemy/engine/base.py", line 1584, in _execute_clauseelement 
    compiled_sql, distilled_params 
    File "/path/python2.7/site-packages/sqlalchemy/engine/base.py", line 1698, in _execute_context 
    context) 
    File "/path/python2.7/site-packages/sqlalchemy/engine/base.py", line 1691, in _execute_context 
    context) 
    File "/path/python2.7/site-packages/sqlalchemy/engine/default.py", line 331, in do_execute 
    cursor.execute(statement, parameters) 
sqlalchemy.exc.InterfaceError 

我如何能做到这一点任何想法？

Answer 1

你能试试这个，让我知道你想说什么？

基本上，我只是把正确的参考变量。

new_artist = models.Artist(
    name = artist_name, 
    ) 
db.session.add(new_artist) 

new_song = models.Song(
    name = song_name, 
    artist = new_artist, 
    ) 
db.session.add(new_song) 

new_media = models.Media(
    song = new_song, 
    media_id = media_id, 
    user=user 
    ) 
db.session.add(new_media) 
db.session.commit()