Thanks for the comment! My post was assuming you ...

2009-05-05T13:32:00.000-04:00

Thanks for the comment! My post was assuming you want to delete the children when you delete the parent, but as you mentioned, you can keep the children around by omitting the cascade= argument. Thanks again!

found this on google - it was kinda helpfull but i...

2009-05-05T12:00:00.000-04:00

found this on google - it was kinda helpfull but i missed one thing:
how to delete a parent without automatically deleting the childs
(solution below)

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after more research etc. i tried the param passive_deletes=True at first:
mapper(ParentClass, parent, properties=dict(children=relation(ChildClass, backref='parent', cascade='all',
passive_deletes=True)))

but this got me an exception as follows:
* Module sqlalchemy.orm.session, line 789, in flush
* Module sqlalchemy.orm.unitofwork, line 233, in flush
* Module sqlalchemy.orm.unitofwork, line 437, in execute
* Module sqlalchemy.orm.unitofwork, line 888, in preexecute
* Module sqlalchemy.orm.dependency, line 347, in preprocess_dependencies

TypeError: unsupported operand type(s) for +: 'NoneType' and 'NoneType' (Also, errors occurred while attempting to render the primary and secondary standard error message.)

i dont really investigated this

---

later i found the solution
it's so simple that i feel like wasted the last 2hours -_-

just dont use the param cascade at all:
mapper(ParentClass, parent, properties=dict(children=relation(ChildClass, backref='parent'))

kind regards :>

Comments on Just a little Python: Cascade Rules in SQLAlchemy

Thanks for the comment! My post was assuming you ...

found this on google - it was kinda helpfull but i...