Repository navigation
Missing named access to result set #445
Description
Hi,
#408 changed the return type for all fetch ops from Mapping to Sequence, because of a change in SQLAlchemy 1.4.
This means Databases doesn't seem to offer any standard way to access the result values by name anymore.
The postgres backend offers a _mapping property and all the other backends are using SQLAlchemy's Row, which means _mapping is also available, but this is not documented as far as I can tell.
In SQLAlchemy the change wasn't intended to remove named access, the returned Row offers the result set as properties instead, like a named tuple, and in SQLAlchemy 2.0 there's a mapping() method on the result.
Could we add a standardized way of accessing the mapping in Databases as well?
Adding the _mapping property to the result set interface would be enough, but maybe there's a better idea.
Another easy way would be to implement __getattr__ on the postgres backend's Record type.
Activity
[-]Missing Mapping access to result set[/-][+]Missing named access to result set[/+]laukhin commentedon Jan 19, 2022
+1 it breaks a whole database layer for my project. It's really unexpected to have such a drastic interface change from minor release like 0.5.3 -> 0.5.4.
aminalaee commentedon Jan 19, 2022
Hi,
Yes you're right, this wasn't expected.
I think the reason behind that might be it wasn't a good idea to document a private property like
_mappingand now with this change, the private property is the only interface left.I think a more standardized way to deal with it would be much nicer, but maybe we could have a fix for it out soon and deal with that later?
Feel free to create a PR for it.
laukhin commentedon Jan 19, 2022
Thank you for the quick response. I've created PR #447 for it, please check it out :)
aminalaee commentedon Jan 19, 2022
As for the named access to the row result maybe we can do this.
The SQLAlchemy
Rowalready has__getattr__throughBaseRowso if we add it to asyncpgRecordthen it should be ok for all drivers.Simple PR for this: https://github.com/encode/databases/pull/448S
collerek commentedon Jan 20, 2022
Please update to 0.5.5 for an immediate fix.
bustbr commentedon Jan 21, 2022
thank you.