Using Visio SDK to extract data & then create diagrams

Question

Hi All, I need to integrate MS Visio with my existing application. I need to extract data(using ADO.net) from the business objects & then create diagrams based on the data extracted using Visio API. All the users having access to this application will have Visio installed on their system and based on the selections they will be able to view the diagrams. Ex: they may want to know the dependencies between two items which are stored in the database. So the minute they select those two items, they should be able to have the diagramatic view of the items & dependencies. I need to know how do I start with this kind of an application. Any help in this regard will be greatly appreciated.