While Data is always associated with SQL, there is a world of data separated from SQL. SQL is a standard way in many cases to persist and work on data, but doesn't span the lifetime/journey of data. Software systems are built on classes, functions and structs, caches, interfaces, buffers. Its common to have hierarchical relationships between data objects. SQL doesn't naturally handle hierarchy, despite the fact it has syntax to do so.
As a software engineer, data modeler, and data engineer, DoD is a weird label applied to anything. I've decades of experience with SQL but don't gravitate towards it. Reality is messy.