Yes Mike will do that, mostly its marshmallow model schema which is creating the object, as I am using Flask + marshmallow for APIs,
apart from that I have another issue, which i am not able to uderstand: I have a many-to-many relationship between 2 models, same as posted above, still ill put the models here package model: class Package(db.Model, BaseMixin): __tablename__ = 'packages' __bind_key__ = 'broker_db' __repr_attrs__ = ["id","name","deletepkg"] __track_attrs__ = ["name","versions"] #attributes id = db.Column(db.Integer, primary_key=True, autoincrement=True) name = db.Column(db.String(100), index=True,unique=True, nullable=False) deletepkg = db.Column(db.Boolean, index=True,nullable=False) instances = db.relationship('Instance', cascade="all,delete",secondary=PACKAGE_INSTANCE_RELATION,back_populates="packages") groups = db.relationship('Group',cascade="all,delete", secondary=PACKAGE_GROUP_RELATION,back_populates="packages") versions = db.relationship('Version',lazy='dynamic') events = db.relationship('Event', backref=db.backref('package', uselist=False),lazy='dynamic') group model: PACKAGE_GROUP_RELATION = db.Table('package_group_relation', db.Column('package_id', db.Integer, db.ForeignKey('packages.id')), db.Column('groupt_id', db.Integer, db.ForeignKey('groupts.id')), info={'bind_key': 'broker_db'} ) class Group(db.Model,BaseMixin): __tablename__ = 'groupts' __repr_attrs__ = ["id","name"] __bind_key__ = 'broker_db' __track_attrs__ = ["name","packages"] id = db.Column(db.Integer, primary_key=True, autoincrement=True) name = db.Column(db.String(100),unique=True) packages = db.relationship("Package",cascade="all,delete",secondary=PACKAGE_GROUP_RELATION,back_populates="groups") events = db.relationship('Event', backref=db.backref('group', uselist=False), lazy='dynamic') def __init__(self, name): self.name = name in this model when i do something like this: p = Package.query.filter_by(name='firefox').first() //here p is Package object, and it has some groups mapped to it p.groups=[] //when i try to empty it, i get this exception *AssertionError: Collection was loaded during event handling. *//though the action is getting performed, putting a try catch is solving it, but why is it coming? though, g.packages=[] this is working fine with no exception Thanks for any kind of help, in advance -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.