2
当预先加载一个孩子的关系,我怎么能只加载父模型的几列:SQLAlchemy的LOAD_ONLY对父模型
这工作,如果我只需要chapters
模式title
列:
session.query(Book)\
.options(joinedload('chapters').load_only('title'))
但是,这将引发一个错误:
session.query(Book.author)\
.options(joinedload('chapters').load_only('title'))
Query has only expression-based entities - can't find property named 'chapters'.
换句话说,我婉吨ORM语法这个SQL:
SELECT
books.author,
chapters.title,
FROM
books JOIN chapters ON book.id = chapters.book_id
非常感谢你。 – norbertpy