CA ERwin Data Modeler (or ERwin for short) is a data modeling and database design tool that is used to create conceptual, logical, and physical data models. ERwin can create the actual database from the physical model, and create different physical implementations from a single logical model. ERwin can also reverse-engineer existing databases into a data model diagram. ERwin works with many database management systems (DBMS). Outputs from the tool include entity-relationship (ER) diagrams and standard or custom reports on all objects in the design (tables, fields, relationships).
While users are charged for the full version of ERwin, there is a free "Community Edition" available for students and others new to modeling to try the functionality of the software on a small dataset. The Community Edition has a limit on the number of objects (25) that can be created in the data model.