Google App Engine Python中是否有等效的SQL View？

Question

I've been learning python by building a webapp on google app engine over the past five or six months. I also just finished taking a databases class this semester where I learned about views, and their benefits.

Is there an equivalent with the GAE datastore using python?

Answer 1

Read-only views (the most common type) are basically queries against one or more tables to present the illusion of new tables. If you took a college-level database course, you probably learned about relational databases, and I'm guessing you're looking for something like relational views.

The short answer is No.

The GAE datastore is non-relational. It doesn't have tables. It's essentially a very large distributed hash table that uses composite keys to present the (very useful) illusion of Entities, which are easy at first glance to mistake for rows in a relational database.

The longer answer depends on what you'd do if you had a view.

Answer 2

First of all answer to your question: With normal GAE, ie non relational DB GAE, you won't have such things as views

Since you are probably starting with Relational SQL in school, I would suggest switch to Relational SQL based GAE at http://code.google.com/apis/sql/ and http://code.google.com/apis/sql/docs/before_you_begin.html#enroll ( I am not sure if it's available right away, or you need to wait for approval to use an instance, but register right away)

Web based applications are using emerging NON relational DBs and you would be benefited by studying them as well. That way you also could understand GAE non relational better. As a basic level start at http://en.wikipedia.org/wiki/NoSQL and then you have many more to explore, specially famous once being Mongo DB, Amazon Simple DB etc.