twenty/packages/twenty-docs/user-guide/data-model/capabilities/relation-fields.mdx
Félix Malfait 161689be18
feat: fix junction toggle persistence and add type-safe documentation paths (#17421)
## Summary

- **Fix junction relation toggle not being saved**: The form schema
wasn't tracking the `settings` field, so changes to
`junctionTargetFieldId` weren't marked as dirty
- **Add type-safe documentation paths**: Generate TypeScript constants
from `base-structure.json` to prevent broken documentation links
- **Create many-to-many relations documentation**: Step-by-step guide
for building many-to-many relations using junction objects
- **Update `getDocumentationUrl`**: Now uses shared constants from
`twenty-shared` for base URL, default path, and supported languages

## Key Changes

### Junction Toggle Fix
- Added `settings` field to the form schema in
`SettingsDataModelFieldRelationForm.tsx`
- Fixed the toggle to properly merge settings when updating
`junctionTargetFieldId`

### Type-Safe Documentation Paths
- New constants in `twenty-shared/constants`:
- `DOCUMENTATION_PATHS` - All 161 documentation paths as typed constants
  - `DOCUMENTATION_SUPPORTED_LANGUAGES` - 14 supported languages
  - `DOCUMENTATION_BASE_URL` / `DOCUMENTATION_DEFAULT_PATH`
- Generator script: `yarn docs:generate-paths`
- CI integration: Added to `docs-i18n-pull.yaml` workflow

### Documentation
- New article:
`/user-guide/data-model/how-tos/create-many-to-many-relations`
- Updated `/user-guide/data-model/capabilities/relation-fields.mdx` with
Lab warning and link

## Test plan
- [ ] Verify junction toggle saves correctly when enabled/disabled
- [ ] Verify documentation link opens correct localized page
- [ ] Verify `yarn docs:generate-paths` regenerates paths correctly
2026-01-25 13:29:20 +01:00

90 lines
3.4 KiB
Text

---
title: Relation Fields
description: Connect records across different objects using relation fields.
---
## Types of Relations
### One-to-Many
One record in Object A can be linked to many records in Object B.
**Example:** One Company can have many People (employees).
### Many-to-One
Many records in Object A can be linked to one record in Object B.
**Example:** Many People can belong to one Company.
### Relations to Multiple Object Types
Some objects can link to multiple object types on one side of the relation.
**Example:** A Note can be attached to one Person AND one Company AND one Opportunity simultaneously. The Note is on the "many" side, connecting to multiple "one" sides.
<img src="/images/user-guide/fields/many-to-one-morph.png" style={{width:'100%'}}/>
Similarly, a Project (on the "one" side) could receive links from multiple People, multiple Companies, and multiple Notes.
<img src="/images/user-guide/fields/one-to-many-morph.png" style={{width:'100%'}}/>
<Warning>
**Import/Export limitation**: Relations pointing to multiple object types are not yet supported for CSV import/export. This is on our roadmap.
</Warning>
### Many-to-Many
Many records in Object A can be linked to many records in Object B.
**Example:** Many People can be linked to many Projects, and vice versa.
Many-to-many relations use a **junction object** pattern: an intermediate object that connects both sides. With the junction relation feature, Twenty displays the final linked records directly, hiding the intermediate object from the UI.
<img src="/images/user-guide/fields/junction-relation-diagram.png" style={{width:'100%'}}/>
<Warning>
**Lab Feature**: Junction relations must be enabled at **Settings → Updates → Lab** before use.
</Warning>
See [How to Create Many-to-Many Relations](/user-guide/data-model/how-tos/create-many-to-many-relations) for a complete step-by-step guide.
## Creating a Relation Field
1. Go to **Settings → Data Model**
2. Select the object where you want to add the relation
3. Click **+ Add Field**
4. Select **Relation** as the field type
5. Choose the target object(s) to relate to
6. Configure the relation settings:
- **Field name on source object**: The name of the relation field on the object you're editing
- **Field name on destination object**: The name of the relation field that will appear on the target object
- Relation type (one-to-many, many-to-one)
7. Click **Save**
## Standard Relations
Twenty comes with pre-built relations between standard objects:
| From Object | To Object | Relation Type |
|-------------|-----------|---------------|
| People | Companies | Many-to-One |
| Opportunities | Companies | Many-to-One |
| Opportunities | People | Many-to-One |
## Best Practices
### Planning Relations
- **Map your data model**: Plan relations before creating them
- **Consider direction**: Think about which object "owns" the relationship
- **Avoid circular dependencies**: Keep your data model clean
### Naming Relations
- **Use clear names**: Make it obvious what the relation represents
- **Be consistent**: Use similar naming patterns across relations
- **Consider both sides**: Name both sides of the relation appropriately
### Performance
- **Don't over-relate**: Too many relations can slow down your workspace
## Limitations
- **Deleting relations** removes the link but not the related records
- **Circular relations** should be avoided for data integrity