Where to document database schema in arc42?

I want to document a software project using the arc42 template. Where can I document the database schema? Is it a building block, so it has to be part of chapter 5 (Building Block View)?

Explain it in chapter 8 (concepts), section "Persistence":

There you both clarify your

• persistence strategy and implementation approach, and
• data model and mapping to internal objects/building-blocks/domain-entities or whatever you use.

I suggest to keep chapter 4 (solution strategy) as brief as possible - better include links to later chapters.