---
title: "Prerequisite tables"
description: "Terminology and form scaffolding that no source model describes."
---

Four tables are not derived from any source specification, because neither openEHR nor FHIR describes them. They are the scaffolding everything else hangs on.

| Table | What it holds |
|---|---|
| [`valueset`](/docs/tables/valueset) | One row per coded field in the schema. |
| [`valueset_code`](/docs/tables/valueset_code) | The codes a value set admits, with the display text that must accompany them. |
| [`form`](/docs/tables/form) | The clinical spine — every entry belongs to a form. |
| [`form_block`](/docs/tables/form_block) | Ordered blocks within a form. |

> `attachment` used to live here too. It is now compiled like any other table, from the FHIR `Attachment` datatype merged with `CLUSTER.media_file.v1` — see [`attachment`](/docs/tables/attachment).