python - SQLAlchemy等效于ActiveRecord中的命名范围

是否有等效的AR命名范围？命名范围基本上是过滤器，可以将其包装在方法中，然后进行链接。

这是http://archives.ryandaigle.com/articles/2008/8/20/named-scope-it-s-not-just-for-conditions-ya-know的示例:

class Article < ActiveRecord::Base

  # Get all articles that have been published
  named_scope :published, :conditions => ['published = ?', true]

  # Get all articles that were created recently
  named_scope :recent, lambda { { :conditions => ['created_at >= ?', 1.week.ago] } }

end

# Get all recently created articles that have been published
Article.published.recent

这是使用Django ORM的示例:http://furrybrains.com/2009/06/22/named-scopes-for-django/

最佳答案

SQLAlchemy具有hybrid attributes，您可以使用它构建任何类型的系统:

from sqlalchemy.ext.hybrid import hybrid_property


class Article(Base):
    @hybrid_property
    def published(self):
        return self.is_published == True

    @hybrid_property
    def recent(self):
        # this relies on the date arithmetic of the target backend
        return datetime.now() - self.created_at >= datetime.timedelta(days=7)


articles = query(Article).filter(Article.published, Article.recent).all()

关于python - SQLAlchemy等效于ActiveRecord中的命名范围，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/14599978/