An entity relationship diagram (ERD) helps database designers review and verify links between tables in a database. An ERD shows a visual representation of primary and foreign keys, which are the columns used to link tables. Microsoft Access includes a diagram utility that lets you create and view an ERD for your Access database. You can also use this diagram to reverse engineer any database.
Open the Microsoft Access database software and open the database in which you want to create the diagram.
Click the "File" menu item and select "New." Click "Software and Database," and then select "Database Model Diagram." A new window opens with a blank diagram.
Click the "Database" menu item and click "Reverse Engineer." Access goes through each table and creates a model diagram of your tables and the tables' relationships to each other.