2009/5/21 风笑雪 <[email protected]> > Before my operation, I'll create a memcache to store current time and > editing entity's key, and timeout is about 1 minute. > If this key already existing in memcache, simply cancel this operation. > After the db operation, I'll check its value. If time has been changed, > I'll raise a rollback exception. >
Note that you can not use memcache to reliably store transient information. A cache will expire *within* the given timeout, so it will expire not later than the timeout, but it can expire less than the timeout, depending on the availability of the memory. I think what you can do is to have Blog and BlogName models. The BlogName's key name is the name of the blog itself, and it has a property that references a Blog instance. Then, editing the names can now be done by simply deleting, adding, and retaining BlogName instances. You can create a single entity group (e.g. same parent) for all the BlogName instances so adding and deleting BlogNames can be done within a transaction. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
