Canonical Data Modeling documents, using Data Modeling techniques, how messages or packets pass between different systems internally in the organization and across different company systems, to do e-business.
Data sometimes vary, across systems, in their definitions. For example, a company may have defined “customer” for a data warehouse constructed 10 years ago and then characterized it another way in a graph database implemented last year. But the company wants all the systems to talk with each other even though they may vary in their dialects. The same problem can happen between companies. For example, Amazon can define customer data differently than different vendors. Yet, Amazon needs to talk with all its e-commerce companies.
Both inter and intra company dialog needs a middleware translator to help the different systems talk with each other, The canonical data model diagrams this design.