Question

在我的应用程序中，可以通过两种方式删除表“files”中的行。直接，如session.delete(file)或级联删除的结果。我想删除文件系统中的文件，数据库行代表的文件，删除行时。我有什么方法可以做到吗？

我的模型看起来像这样：

class File(ModelBase):
    """Model for the 'files' table.

    This table holds data about uploaded files.
    """

    __tablename__ = 'files'

    # Columns
    id = Column(INTEGER, primary_key=True)
    uploaded_by_id = Column(INTEGER, ForeignKey(User.__tablename__ + '.id'),
                            nullable=False)
    path = Column(VARCHAR(255), nullable=False) # The file's name on the server
    name = Column(VARCHAR(255), nullable=False) # The original file name
    mime = Column(VARCHAR(75))
    size = Column(INTEGER, nullable=False)   # File size in bytes
    uploaded_at = Column(DATETIME, nullable=False)

    # Relationships
    uploaded_by = relationship('User', backref='files_uploaded')

    def __init__(self, uploaded_by, path, name):

        with ProjectRootContext():
            self.uploaded_by = uploaded_by
            self.path = path
            self.name = name
            self.mime = mimetypes.guess_type(path)[0]
            self.size = os.path.getsize(path)
            self.uploaded_at = datetime.now()

    def __repr__(self):
        return '<File(id=%s,name=%s)>' % (repr(self.id), repr(self.name))

    # Factory function for saving an uploaded file
    @classmethod
    def from_fieldstorage(cls, uploaded_by, fieldstorage):
        # ...

Answer 1

你有没有试过after_delete mapper event？

我可以向SQLAlchemy中的模型添加一个事件，该事件在删除项目时会触发吗？

1 个答案: