15c52d3a39
Add missing info about how to edit navigation bar, add many-to-many relation and get Enterprise key for Org license on self-hosted --------- Co-authored-by: Charles Bochet <charles@twenty.com>
171 lines
6.2 KiB
Plaintext
171 lines
6.2 KiB
Plaintext
---
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title: Create Many-to-Many Relations
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description: Connect records where many items on both sides can be linked together using junction objects.
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---
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Many-to-many relations let you connect multiple records on both sides. For example: many People can work on many Projects, and each Project can have many People.
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<Warning>
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**Lab Feature**: Junction relations are currently in the Lab. Enable them at **Settings → Updates → Lab** before following this guide.
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</Warning>
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<Note>
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This feature also requires **Advanced mode** to be enabled (toggle at the bottom right of Settings).
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</Note>
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## When to Use Many-to-Many
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Use many-to-many when both sides of a relationship can have multiple connections:
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| Relationship | Example |
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|-------------|---------|
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| People ↔ Projects | A person works on multiple projects; a project has multiple team members |
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| Companies ↔ Tags | A company can have multiple tags; a tag can apply to multiple companies |
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| Products ↔ Orders | A product can be in multiple orders; an order contains multiple products |
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## How It Works
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Twenty uses a **junction object** pattern for many-to-many relations. A junction object sits between two objects and holds the connections:
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```
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People ←→ Project Assignments ←→ Projects
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```
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The **Project Assignments** object (junction) has:
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- A relation to People (many-to-one)
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- A relation to Projects (many-to-one)
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When you enable the junction relation toggle, Twenty displays linked records directly instead of showing the intermediate junction records.
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## Prerequisites
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1. **Enable Junction Relations in Lab**: Go to **Settings → Updates → Lab** and enable **Junction Relations**
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2. **Enable Advanced mode**: Toggle on **Advanced mode** at the bottom right of the Settings sidebar
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3. Plan your data model:
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- Which two objects are you connecting?
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- What should the junction object be called?
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## Step 1: Create the Junction Object
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First, create the intermediate object that will hold the connections.
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1. Go to **Settings → Data Model**
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2. Click **+ New object**
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3. Name it descriptively (e.g., "Project Assignment", "Team Member", "Product Order")
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4. Toggle "Skip creating a Name field" on
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<img src="/images/user-guide/fields/new-pivot-object.png" alt="New pivot object" />
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5. Click **Save**
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<Tip>
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**Naming convention**: Use a name that describes the relationship, like "Project Assignment" or "Team Membership". This makes the data model easier to understand.
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</Tip>
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## Step 2: Create Relations Between Objects and the Junction
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Add relation fields from each of your two objects to the junction object.
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### First Relation (Object A → Junction)
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1. Select your first object in **Settings → Data Model**
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2. Click **+ Add Relation**
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3. Select the junction object (e.g., "Project Assignments")
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4. Set the relation type to **One-To-Many** (one person can link to many assignments)
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5. Name the fields:
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- Field on People: e.g., "Project Assignments"
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- Field on junction: e.g., "Person"
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6. Click **Save**
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### Second Relation (Object B → Junction)
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1. Select your second object in **Settings → Data Model**
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2. Click **+ Add Relation**
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3. Select the junction object (e.g., "Project Assignments")
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4. Set the relation type to **One-To-Many** (one project can link to many assignments)
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5. Enable **"This is a relation to a Junction Object"**
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<img src="/images/user-guide/fields/junction-relation-toggle.png" style={{width:'100%'}}/>
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6. Name the fields:
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- Field on junction: e.g., "Project"
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- Field on Projects: e.g., "Team Members"
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7. Click **Save**
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## Step 3: Configure the Junction Relation Display
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Now configure the source objects to display linked records directly, skipping the intermediate junction object.
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1. Go to **Settings → Data Model**
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2. Select the first object (e.g., "People")
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3. Find the relation field pointing to the junction object (e.g., "Project Assignments")
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4. Click to edit the field
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5. Enable **"This is a relation to a Junction Object"**
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6. Select the **Target relation** (e.g., "Project" — the field on the junction that points to the other side)
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7. Click **Save**
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## Result
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After configuration:
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- On a **Person** record, the "Project Assignments" field displays **Projects** directly (not assignment records)
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- On a **Project** record, the "Team Members" field displays **People** directly
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The junction object still exists and stores the connections, but the UI presents a cleaner many-to-many view.
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## Example: People ↔ Projects
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Here's a complete walkthrough:
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### Create the Junction Object
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- Name: **Project Assignment**
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- Description: "Links people to projects they work on"
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### Add Relations
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1. **People → Project Assignment**
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- Type: One-to-Many
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- Field on People: "Project Assignments"
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- Field on Assignment: "Person"
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2. **Projects → Project Assignment**
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- Type: One-to-Many
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- Field on Projects: "Team Members"
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- Field on Assignment: "Project"
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### Configure Junction Display
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1. On **People** object:
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- Edit "Project Assignments" field
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- Enable junction toggle
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- Target: "Project"
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2. On **Projects** object:
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- Edit "Team Members" field
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- Enable junction toggle
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- Target: "Person"
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### Use It
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- Open a Person record → See their Projects directly
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- Open a Project record → See team members directly
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- Create new connections from either side
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## Adding Extra Data to Connections
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Since the junction object is a real object, you can add custom fields to store information about the relationship:
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- **Role**: "Developer", "Designer", "Manager"
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- **Start Date**: When they joined the project
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- **Hours Allocated**: Weekly hours on this project
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To access this data, navigate to the junction object directly or query it via the API.
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## Limitations
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- **CSV Import/Export**: Importing many-to-many relations directly is not supported. Import records to the junction object instead.
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- **Filters**: Filtering by many-to-many relations may have limited options.
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## Related
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- [Relation Fields](/user-guide/data-model/capabilities/relation-fields) — relation types explained
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- [Create Custom Objects](/user-guide/data-model/how-tos/create-custom-objects) — how to create objects
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- [Create Relation Fields](/user-guide/data-model/how-tos/create-relation-fields) — basic relation setup
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