Flask 级联删除

• 例如

###  只删除父级，子不影响
# api = db.relationship('Api', backref='project',  passive_deletes=True)

###  子级跟随删除
# 2. api = db.relationship('Api', backref='project', cascade="all, delete-orphan")
# 3. api = db.relationship('Api', backref='project', cascade="all, delete")