Creating Entity Relationship Diagram in Visio It is a common task for a developer to build an Entity Relationship (ER) Diagram for an existing database. If you are dealing with an MS SQL Server, this can be done easily within SQL Server Management Studio, but what if you are given a database in MS Access, PostgreSQL, or MySQL. There are tools (such as ModelRight) to help you with this, but if you have got MS Visio Professional Edition, you have another option. Since Visio 2003, a new feature, Reverse Engineer, has been made available in its Professional edition (and Premium edition in Visio 2010). This feature allows you to connect to an existing database, extract database schema, and create an ER Diagram automatically. You can also lay things out in the way that you want, and catch changes made to the database. The key here is to create a connection to your database. It does not have to be a Microsoft database. Most likely, if there is an ODBC D