SQLAlchemy: Modification of detached object

Question

I want to duplicate a model instance (row) in SQLAlchemy using the orm. My first thought was to do this:

i = session.query(Model)
session.expunge(i)

old_id          


        

Answer 1

this case is available using the make_transient() helper function:

inst = session.query(Model).first()
session.expunge(inst)

make_transient(inst)
inst.id = None
session.add(inst)
session.flush()
print inst.id #New ID

Answer 2

def duplicate(self):
    arguments = dict()
    for name, column in self.__mapper__.columns.items():
        if not (column.primary_key or column.unique):
            arguments[name] = getattr(self, name)
    return self.__class__(**arguments)