(I haven't used any of these features, so the following is just a guess)
In your assertion, you are comparing two *Point instances*. The SQLAlchemy
comparator_factory mechanism has not made any changes to the Point class
itself, and Point doesn't define __gt__, hence your TypeError.
The point of the comparator_factory is to add class-level behaviour when
you are building SQL expressions. In this case, you could write a query
like this:
query = dbsession.query(Vertex).filter(Vertex.start > Point(2, 2))
Hope that helps,
Simon
On Fri, Sep 16, 2022 at 9:38 AM jens.t...@gmail.com <jens.troe...@gmail.com>
wrote:
> Hello,
>
> I’m noodling through the Composite Column Types
> <https://docs.sqlalchemy.org/en/14/orm/composites.html> examples, and
> can’t make it work. Based on the code on that page I put together a minimal,
> reproducible example
> <https://stackoverflow.com/help/minimal-reproducible-example> (attached)
> which fails with
>
>
>
>
>
> *Traceback (most recent call last): File "/path/to/test.py", line 75, in
> <module> assert v1.start > v2.startTypeError: '>' not supported between
> instances of 'Point' and 'Point'*
>
> Why is that? What am I missing? I expected to see SQL generated that
> implements the “greater than” between two *Point* instances (or perhaps
> *Vertex* instance, not sure, probably not).
>
> Much thanks!
> Jens
>
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