8.30. SQLAlchemy Query About
8.30.1. Query
8.30.2. With Session
8.30.3. Select Columns
https://docs.sqlalchemy.org/en/stable/orm/loading_columns.html#sqlalchemy.orm.defer
https://docs.sqlalchemy.org/en/stable/orm/loading_columns.html#sqlalchemy.orm.deferred
https://docs.sqlalchemy.org/en/stable/orm/loading_columns.html#sqlalchemy.orm.load_only
from sqlalchemy.orm import defer
from sqlalchemy.orm import undefer
session.query(Book).options(
defer('*'), undefer('summary'), undefer('excerpt'))
A similar function is available with less verbosity by using the load_only() option. This is a so-called exclusionary option which will apply deferred behavior to all column attributes except those that are named:
from sqlalchemy.orm import load_only
session.query(Book).options(load_only(Book.summary, Book.excerpt))