Hi, first at all i must say that i come from the relational database world. I have a few doubts about how datastore works being schemaless.
For example, let's say that i have a presistent class User that haves only 3 propertys: id (int), username (String) and password (String). So, i deploy my application on appengine and create a user with username = "ian" and password = "ian123". And then i make a query, searching all the users, and i get the user "ian". Ok, until here i understand this perfect. DOUBT 1: What happens, if i make a change to the User class and, for example, i add to the class the property sex (String). Then i deploy my app again in the appengine. Now i create a new user with this values username = "mcculloch", password = "mc123" and sex = "M" and persist the user. I think that if i make the query to get all the useri will get the 2 users, and the property sex to the user "ian" will be null. Is that correct? DOUBT 2: Now i realize that i don't want to store the sex of the user, and also i think that i don't want the id property as an integer. Now i want that the username will be the key of the class, so i remove the id property and add the annotation to make the username property the Primary Key of the entity. Then i deploy the app on appengine, create a new user with this values: username = "eric", password = "eric123". What does happen now i query all the users, will i get the two users? DOUBT 3: Let's say that i realize that i really need the sex property for the users, so i add again the sex property to the User class and deploy again to the datastore. If i query for all the users? What datastore will return to me? All the users? Only those that the sex is not null? DOUBT 4: Finally, what happens if i want to have 2 enviroments of my app? I have to create 2 apps on appengine? If this is the way, let's supose that in my production enviroment i have a lot of data and i want to make a copy of that data to my testing app so i can make testing with good data. Can i copy that data from one app to another? How could i? -- 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-appeng...@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.
