Mongoid ::包含 Mongoid::Includes改善Mongoid::Includes渴望加载，支持多态关联和嵌套的渴望加载。 用法 Album . includes ( :songs ) . includes ( :musicians , from : :band ) Band . includes ( :albums , with : -> ( albums ) { albums . gt ( release : 1970 ) } ) # The library supp