On Thu, Oct 8, 2020 at 3:38 AM Richard Damon <[email protected]> wrote: > > I am working on a app using SQLAlchemy's ORM layer to interface to the > database, but I am running into an issue that if an object has > 'complicated' property, like a UUID, that SQLAlchemy doesn't know how to > handle. One option would be to make the propery actually only hold a > database suitable representation, and I see an option to add a > 'reconstructor' to convert a value read from the database into an > object. Is there a similar way that when writing the object, to indicate > how to convert the object into a format that can be put into the database? >
The usual pattern is to create a custom datatype using sqlalchemy.types.TypeDecorator. You would override the process_bind_baram and process_result_value methods to convert objects between the python and database representations: https://docs.sqlalchemy.org/en/13/core/custom_types.html#augmenting-existing-types For the specific case of UUIDs, there is an example in the docs that will use Postgres' UUID type against postgres, and CHAR against other databases: https://docs.sqlalchemy.org/en/13/core/custom_types.html#backend-agnostic-guid-type Hope that helps, Simon -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/CAFHwexeVbT%3DAN%2BBTxNVoMY0PY3U7rTK73d1XHcbZYM%2BkQpp1RA%40mail.gmail.com.
