On Sat, Feb 21, 2009 at 11:44 PM, Yarko Tymciurak <yark...@gmail.com> wrote:
> I may be missing something (I have just started to read this) but I have a > fundamental question: > It seems to me entity groups (no matter how "limited" you consider them) > are also useful and critical for things like updating, say, a user > registration to a conference which may very well involve more than one table > item: > > person.id and registration.id and payment.id and coupon.id (for example). > you are right... without entity groups you do not have transactions.... and therefore you must implement the rollback programmatically (mmmm..... bad !!!!) > > It seems to me "entity group" is a useful concept that should scale accross > to SQL dbs in some way also. By not abstracting this appropriately, it > seems we are creating (practically looking at this) more limitations than > GAE has in reality. > you are right on that. GAE introduces a lot of limitations in change of some great benefits... to overcome (partially) those limitations we need to use all what GAE can offer.... otherwise we get limited twice ! > > Am I missing something? > probably we can use web2py as long as it help us reducing the coding/maintaining time... and complement it with GAE API bypassing the DAL.... > > Thanks, > Yarko > > On Fri, Feb 20, 2009 at 11:33 AM, Robin B <robi...@gmail.com> wrote: > >> >> The only easy way to set parent= is to bypass the DAL, because you do >> not get easy access to the google key for the entity that is needed to >> set a parent=. >> >> To use Google specific stuff, you can use the gae_db.Model directly. >> >> To effectively use Google logins, you *must* use gae_db.UserProperty >> (users can change the email associated with their google account, so >> it is the only way to reliably/uniquely identify a user). >> >> For example, I use this for Google users on http://ru.ly: >> >> class GaeUsers(gae_db.Model): >> user = gae_db.UserProperty() >> created_at = gae_db.DateTimeProperty(auto_now_add=True) >> >> def get_current_user(): >> user = gae_users.get_current_user() >> local_user = None >> if user: >> local_user = GaeUsers.all().filter('user =',user).get() >> if local_user is None: >> local_user = GaeUsers(user=user) >> local_user.put() >> return local_user >> >> >> Robin >> >> >> On Feb 20, 11:13 am, "Sebastian E. Ovide" <sebastianov...@gmail.com> >> wrote: >> > On Fri, Feb 20, 2009 at 12:36 AM, Robin B <robi...@gmail.com> wrote: >> > >> > > I have the transactions working, but it is not fully compatible with >> > > web2py DAL, but it could be soon ( needs type coercion, db.table.ALL, >> > > etc) Also in web2py, you cannot set the entity group when inserting, >> > > so transactions will only involve 1 record. (eg atomically read/ >> > > modify/write a counter in a transaction) >> > >> > that is great, at least we can do counters !... >> > >> > and how could we specify a parent in a antity with web2py ? is there any >> > simple way ? >> > >> > thanks ! >> > >> > >> > >> > > If you needed transactions immediately, you could do this: >> > >> > > from google.appengine.ext import gdb >> > >> > > def txn(): >> > > post = db.posts[post_id] >> > > post.update_record(title='foo') >> > > return post >> > >> > > post = gdb.run_in_transaction(txn) >> > >> > > On a side note, I have batch operations working too. But I recently >> > > read that batch operations are just O(n), which unfortunately means no >> > > joins or efficient batch operations will be possible for now, but I >> > > have not benchmarked it on the real google datastore to know for sure. >> > >> > > Robin >> > >> > > On Feb 19, 3:31 pm, sebastian <sebastianov...@gmail.com> wrote: >> > > > Hi All, >> > >> > > > is there any schedule for the GAE transactions/entity groups ? >> > >> > > > if not, how would it be the best way (web2py upgrades compatible !) >> to >> > > > use entity groups and transaction with web2py ? >> > >> > > > thanks >> > >> > > > On Jan 19, 2:59 pm, Robin B <robi...@gmail.com> wrote: >> > >> > > > > > Groups under the DAL to be a single record. Since Big Table >> > > > > > transactions are limited to one Entity Group pertransaction, >> this >> > > > > > means that we are limited to one record pertransaction. Right? >> > >> > > > > You have it right. >> > >> > > > > > In the example above, 'count' is just an example of some >> arbitrary >> > > > > > column in the record, right? Can I have multiple assignments? >> Can I >> > > > > > mix lambda and non-lambda assignments? E.g.: >> > >> > > > > > row.update_record(count=lambda r: r.count+1, >> vote_score=lambda r: >> > > > > > calculate_vote_score(), preference='blue') >> > >> > > > > Yes, you would be able to mix lamdas/functions and values. >> > >> > > > > On the subject of passing lamdas as attributes, the field.default= >> > > > > should also recognize any lambda/callable and call it on demand: >> > >> > > > > def uuid(): >> > > > > import uuid >> > > > > return uuid.uuid4() >> > >> > > > > db.table.created_at.default=t2.now >> > > > > db.table.uuid.default=uuid >> > >> > > > > Robin >> >> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to web2py@googlegroups.com To unsubscribe from this group, send email to web2py+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
