What it means is that if you want to update multiple objects in a transaction they HAVE to be in the same entity group, have a parent-child relation.
It is good practice to use the parent-child relation if you need to find the parent based on the child instance. parent_key = child_inst.key().parent() It is bad practice to have a lot of child instances in one (1) entity group that you write a lot too. This will lead to conflicts and write misses. It is usable if you read a lot from this entity group, no conflict for reading. 2009/12/29 alf <[email protected]>: > Hello what do you think. > > we are a little confuse about parent and child. I have read that only > shold be use in transacction (ok), not split along server, write > neckbootle ok. But in i/o 2009 video show that is a good solution > split models in two class like: > > a>message (db.model) > from > comments > > b>messageindexes (db.model) > to liststringproperty() > > when (a) i parent of (b) > > > If in a doc say only use in transacction and etc. what happen if in > this enviroment exist million of records is a good or bad design. > > many thanks > > -- > > 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. > > > -- 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.
