Semarchy does master data management, meaning it unifies and standardizes all kinds of data, including customer identities. It makes a point of giving control to business users instead of IT departments, which is another big CDP selling point. But, unlike a CDP, Semarchy doesn’t store detailed data such as transaction histories.  Here’s where Denodo comes in: Denodo is a data virtualization system, meaning it lets applications access data where it resides, which is usually the operational system that created it.. Virtual access can be useful for CDPs, but copying data into a central system is best for key functions including data cleansing, identity resolution, trend analysis, and real-time access. Semarchy and Denodo just announced a strategic partnership to collaborate in marketing their products. Such partnerships don’t usually amount to much because the sales forces have their own priorities and rarely understand the partner products.  But this still means that buying CDPs just got even more confusing.