[odb-users] Re: any access to sequence without explicitly naming it?

[NIkolai Marchenko]

It's further compounded by the fact that pre-persist callbacks are const
only. so to even query that sequence I have to write my own pre-persist
hook to call for these objects that lives completely outside odb
architecture.

On Sun, Aug 31, 2025 at 8:52 AM NIkolai Marchenko <enmarantispam at gmail.com>
wrote:

> Note: the name of the initial message may be misleading and I may be in
> need of an entirely different solution.
>
> I have encountered a weird use case trying to use the new points_to
> functionality that I am not sure how to deal with:
>
> suppose an object contains another object. an inner objects points_to the
> outer object with on delete cascade option and both are not persistent yet.
> The objects both have auto id quint64 keys. Since they both don't have id
> yet, I cannot assign an id to points_to and when I persist the _outer_
> object it says that inner isn't persistent yet. but when I persist an
> _inner_ object it also fails because foreign key constraint is not
> satisfied. the schema is created with deferred constraint checking ... but
> I they need to have matching ids beforehand.
>
> The only way I see of breaking this loop is to access a sequence for the
> outer object inisde the transaction and reserving the key to it that I can
> feed into points_to... but as far as I can see odb doesn't have a native
> function to access a sequence. This means I have to .execute("raw sql
> here") and this is potentially breaking on refactors. Am I missing
> something obvious on how to deal with those?
>