How to get value or name of enum from SQLAlchemy result query?

1. Is there a way to override the return value of GenderEnum.l to the value or name by doing something in GenderEnum class?

That’s not really what Enums are meant to do, but you can access the name and value of your enum via the name and value attributes. In fact, SQLAlchemy will store the name of the Enum in the database in most cases.

2. Is there a way I can get the value or name of GenderEnum when I query the data from the database?

You define your model with an gender as an enum, so when loading, that is what you will get.

3. Or a way to make the query call the gender value or name as the default instead the enum object?

Same answer as above, you define gender as an enum, so SQLAlchemy gives it to you.

But to fix your problem, I can only recommend you look into dependency inversion.

Have a model which corresponds to your logic and allows you to solve the problem, then this model can be mapped to an entity, which allows you to store the model in whatever persistance layer, and finally a converter/serialiser for your model to load from/dump to your API.

This way, your model is not tied to where you store it or how you recieve it.

Slightly simplified example from your code:

# model.py
from dataclasses import dataclass, field
from enum import Enum, auto


class GenderEnum(Enum):
    p = auto()
    l = auto()


@dataclass
class ActivityLevel:
    id: int = field(init=False)  # NOTE add `repr=False` if trying to display instances
    name: str
    gender: GenderEnum

# orm.py
from sqlalchemy import Column, Enum, ForeignKey, Integer, String, Table
from sqlalchemy.orm import registry

from .model import ActivityLevel

mapper_registry = registry()

activity_level = Table(
    "activity_level",
    mapper_registry.metadata,
    Column("id", Integer, primary_key=True),
    Column("name", String(100), nullable=False),
    Column("gender", Enum(GenderEnum), nullable=False),
)


def start_mapper():
    mapper_registry.map_imperatively(ActivityLevel, activity_level)

# serialiser.py
from json import JSONDecoder, JSONEncoder

from .model import ActivityLevel, GenderEnum


class ActivityLevelJSONEncoder(JSONEncoder):
    def default(self, o):
        try:  # NOTE duck typing and asking for forgiveness not permission
            return {
                "name": o.name,
                "gender": o.gender.name,
            }
        except AttributeError:
            return super().default(self, o)


class ActivityLevelJSONDecoder(JSONDecoder):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, object_hook=self._object_hook, **kwargs)

    @staticmethod
    def _object_hook(d: dict) -> ActivityLevel:
        return ActivityLevel(
            name=d["name"],
            gender=GenderEnum[d["gender"]],
        )

Then in during application startup, start the mappers, and whenever needed json.dumps your ActivityLevel instances with the kwarg cls=ActivityLevelJSONEncoder.