Anyone knows how to define unique constraint in datastore? See I have a Blog model, and it has these properties: name, content, title, keywords, description and so on.
I need provide a URL to get this blog like this: http://<domain>/blog/<name>.html So user cannot have two blogs that share the same name, otherwise one of them cannot be gotten via URL. I also need provide a way to change blogs' names. It seems I need to define a BlogName model to store Blog's name as keyname, and start a transaction to store the 2 entities: Creating: 1. Get BlogName entity by keyname, if not exsit, create one, else exit as failed. 2. Create a Blog entity which parent and name is this BlogName entity. Editing: 1. Get BlogName entity by keyname, if not exsit, create one, else exit as failed. 2. Get the old Blog entity and old BlogName entity by keyname. 3. Create a Blog entity which parent and name is this BlogName entity, and rest the same to the old one. 4. Delete the old 2 ones. Well, it seems can work, but how terrible it is! And if I want a blog can have multiple names, so the two URLs can get the same blog: http://<domain>/blog/hello.html http://<domain>/blog/你好.html I don't think I can get them by keyname since they are in a list property now, so it can't be done in a transaction. And if I keep them in two Blog entities, I need change both of them when I edit one of its properties. So it seems I need define BlogContent model, BlogTitle model, BlogKeywords model, BlogDescription model for referece from Blog model. Any better idea for me? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
