A common question from people who use the Database Model Diagram template in Microsoft Office Visio is "What happened to the Generate and Update commands?"
The short answer is that the Generate and Update commands are not available in the Standard and Professional editions of Microsoft Office Visio 2003 or Microsoft Office Visio 2007.
You can find the full suite of database modeling features, including the Generate and Update commands, in Microsoft Office Visio for Enterprise Architects. Visio for Enterprise Architects is included in the MSDN Premium Subscription, which is available with Microsoft Visual Studio Professional and Visual Studio Team System role-based editions.
Visio Standard and Visio Professional cannot generate a database, such as a Microsoft Office Access or Microsoft SQL Server database, from a database model diagram. Nor can they update a physical database from changes that you make to your model diagrams.