Winter '12 Force.com Platform Release
Schema Builder (Beta)

You can now view a read-only diagram of the elements of your schema all in one window. This tool works for Force.com and Database.com.

Schema builder eliminates the need to click from page to page to find the details of objects, fields, and relationships in your schema.

Each object includes details such as the field values, required fields, and how objects are related by displaying lookup and master-detail relationships. The drag-and-drop interface lets you easily move objects around and saves the layout of your schema any time you move an object.