如何将外部数据库连接到AppEngine？
有什么方法（优于使用 UrlFetch ）连接到AppEngine中的任何外部数据库？
Are there any ways (better than using UrlFetch) to connect to any external database from AppEngine?
我已经了解 App Engine for Business 中的托管SQL数据库，但他们不是免费的，将在2011年第二季度可用，所以它现在不是一个选择。
I already know about hosted SQL databases in App Engine for Business, but they are not free and will be avialable in Q2 2011, so it's not an option right now.
我非常喜欢数据存储，但客户不喜欢供应商锁或有其他原因。
I like datastore very much, but customers don't like vendor lock or have other reasons.
将外部数据库连接到AppEngine的唯一方法是通过Web API公开它们。 >
基本上，您需要在数据库上创建一个webservices层，允许您的GAE应用程序通过 UrlFetch Http调用。
The only way to connect external databases to AppEngine is by exposing them via a web API.
Basically you need to create a webservices layer upon your Database, allowing your GAE Application to interact with the remote db through UrlFetch Http calls.