CA ERwin Data Modeler (ERwin) is a software tool for data modeling (data requirements analysis, database design etc.) of custom developed information systems, including databases of transactional systems and data marts. ERwin's data modeling engine is based upon the IDEF1X method, although it now supports diagrams displayed with information engineering notation as well. Logic Works stylised "ERwin" from an abbreviation of "Entity Relationships" and Microsoft's "Windows".