The Data Management Body of Knowledge is the closest thing the profession has to a shared textbook. It defines eleven knowledge areas — governance, architecture, modeling, storage and operations, security, integration and interoperability, document and content, reference and master data, warehousing and business intelligence, metadata, and data quality — and draws them as a wheel with governance at the hub. It is a vocabulary and a checklist, not a methodology: it tells you what exists and what each part is for, and leaves the sequencing to you.
In practice. Its most useful function is as a gap map. Run a program against the eleven areas and the two or three nobody owns become visible immediately, which is usually more informative than any maturity score. It also settles arguments about words, which is why the CDMP certification is built on it.
Where it goes wrong. Teams treat the wheel as a plan and try to stand up eleven capabilities at once. The wheel is a map of the territory, not a route through it. A first year that does governance, metadata and quality properly on one domain beats a first year that opens eleven workstreams and finishes none.