In our last blog of this series Walkthrough of creating a SharePoint 2010 external list using Visual Studio 2010 Beta , we introduced how to create a simple “Hello world” external list in SharePoint 2010 Beta using Business Data Connectivity Designer in Visual Studio 2010 Beta. In this blog, we will show you how to pull data from an external database into an external list and enable Create, Read, Update and Delete (CRUD) functions to the external list.

Here is the original: 
Walkthrough of enabling CRUD for SharePoint 2010 external lists using Visual Studio 2010