for循环SQLAlchemy (flask)中的更新表

Question

我正在尝试执行以下操作:循环遍历dict中的一系列项，并将每个项添加到表的新行中。

由于某些原因，加法只适用于循环的最后一项。下面是我的代码的一部分：

    ######
    # Model of interface_traffic table
    class InterfaceTraffic(UserMixin, db.Model):
        id = db.Column(db.Integer, primary_key=True)
        #
        network_device_id = db.Column(db.Integer, db.ForeignKey('network_device.id'))
        #    
        interface = db.Column(db.String(50), index=True, unique=False)
        traffic_in = db.Column(db.String(10), index=True, unique=False, default=0)
        traffic_out = db.Column(db.String(10), index=True, unique=False, default=0)

        def __repr__(self):
            return '<Interfaces Traffic For NetworkDevice ID: {}>'.format(self.network_device_id) 


    ######
    # Object From Models Tables (interface_traffic table)
    interface_traffic = InterfaceTraffic()
    hostname_for_id = NetworkDevice.query.filter_by(hostname=hostname).first()

    # Dict From Method check_interface_traffic(), provided by host Object Instance of Class NetworkElement
    traffic_on_interfaces = host.check_interface_traffic()

    # Populating Database Params
    for interface, traffic in traffic_on_interfaces.items():
        # interface_traffic.network_device_id is a foreign key
        interface_traffic.network_device_id = hostname_for_id.id
        interface_traffic.interface = interface
        interface_traffic.traffic_in = traffic[0]
        interface_traffic.traffic_out = traffic[1]
        db.session.add(interface_traffic)
        # I tryed with commit in each loop, but has the same behavior
        # db.session.commit()

    # I tryed with flush too, but has the same behavior
    # db.session.flush()
    db.session.commit()

Answer 1

您需要在for循环中创建InterfaceTraffic()，否则它将被覆盖。

for interface, traffic in traffic_on_interfaces.items():
    interface_traffic = InterfaceTraffic() #HERE
    interface_traffic.network_device_id = hostname_for_id.id
    interface_traffic.interface = interface
    interface_traffic.traffic_in = traffic[0]
    interface_traffic.traffic_out = traffic[1]
    db.session.add(interface_traffic)
db.session.commit()