How to write an external db SPI?

Where would I learn how to write an external db SPI? I’m a programmer with a great deal of SQL experience writing user applications using SQL data. I’d like to make some of SQL data visible to a Wix website, but I don’t know where to start regarding the creation of a external database adapter.

Hello.

If you are using MySQL, follow the guidelines here: Adapter for MySQL databases deployed to Google AppEngine

For general guidelines, refer to this article: Working with External Database Collections

Good luck!