---
title: "Terminology"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Terminology}
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  %\VignetteEncoding{UTF-8}
---

These terms describe forms and their definitions in `form.model`.

## Main concepts

| Term       | Meaning                                                                                           |
|------------|---------------------------------------------------------------------------------------------------|
| Form       | An Excel workbook used to collect data.                                                           |
| Form model | A versioned YAML definition of a form’s sheets, fields, layout and constraints.                   |
| Consumer   | A package, tool or application using a form model to import, export, validate or transform forms. |

## Form model definition

### Structure

| Term   | Meaning                                                                              |
|--------|--------------------------------------------------------------------------------------|
| Sheet  | A worksheet within a form, containing fixed cells or repeated records.               |
| Field  | A named item of data with a declared type and a position in the form.                |
| Record | One row of related field values in a sheet with a table layout.                      |
| Layout | The arrangement of fields in fixed cells or table columns, with declared dimensions. |

### Validation declarations

| Term        | Meaning                                                                                 |
|-------------|-----------------------------------------------------------------------------------------|
| Field type  | The kind of value a field accepts, such as text, an integer, a date or a boolean.       |
| Constraint  | A requirement on a field or record, such as requiredness, allowed values or uniqueness. |
| Primary key | One or more fields whose combined values identify a record within a sheet.              |
| Parent key  | Fields that connect a record to the primary key of a record in another sheet.           |

### Reference declarations

| Term                | Meaning                                                                             |
|---------------------|-------------------------------------------------------------------------------------|
| Reference catalogue | A named collection of reference tables available from a configured source.          |
| Reference table     | A table of reference records, such as countries, stations or contacts.              |
| Lookup              | A named way to find rows in a reference table using a column and matching settings. |
| Reference binding   | A field’s declaration of the catalogue, table and lookup used to check its value.   |