When PersistentDict, when Folder?
问题 When should I use a PersistentDict, and when should I use a Folder? What is the difference between them in terms of updates, internal structure, performance, etc? 回答1: A PersistentMapping is simply a implementation of the python dict type (via the standard library UserDict base class) adjusted for the Persistence semantics of the ZODB; it saves from having to set the _p_changed flag on the nearest class that inherits from Persistent every time you alter the mapping . A Folder is a much richer