Documentation Index
Fetch the complete documentation index at: https://docs.twenty.com/llms.txt
Use this file to discover all available pages before exploring further.
Relations connect two objects together. In Twenty, relations are always bidirectional — every relation has two sides, and each side is declared as a field that references the other.
| Тип отношения | Описание | Есть внешний ключ? |
|---|
MANY_TO_ONE | Многие записи этого объекта указывают на одну запись целевого объекта | Да (joinColumnName) |
ONE_TO_MANY | Одна запись этого объекта имеет много записей целевого объекта | No (the inverse side) |
How relations work
Every relation requires two fields that reference each other:
- The MANY_TO_ONE side — lives on the object that holds the foreign key.
- The ONE_TO_MANY side — lives on the object that owns the collection.
Both fields use FieldType.RELATION and cross-reference each other via relationTargetFieldMetadataUniversalIdentifier.
Example: Post Card has many Recipients
A PostCard can be sent to many PostCardRecipient records. Each recipient belongs to exactly one post card.
Step 1: Define the ONE_TO_MANY side on PostCard (the “one” side):
src/fields/post-card-recipients-on-post-card.field.ts
import { defineField, FieldType, RelationType } from 'twenty-sdk/define';
import { POST_CARD_UNIVERSAL_IDENTIFIER } from '../objects/post-card.object';
import { POST_CARD_RECIPIENT_UNIVERSAL_IDENTIFIER } from '../objects/post-card-recipient.object';
// Export so the other side can reference it
export const POST_CARD_RECIPIENTS_FIELD_ID = 'a1111111-1111-1111-1111-111111111111';
// Import from the other side
import { POST_CARD_FIELD_ID } from './post-card-on-post-card-recipient.field';
export default defineField({
universalIdentifier: POST_CARD_RECIPIENTS_FIELD_ID,
objectUniversalIdentifier: POST_CARD_UNIVERSAL_IDENTIFIER,
type: FieldType.RELATION,
name: 'postCardRecipients',
label: 'Post Card Recipients',
icon: 'IconUsers',
relationTargetObjectMetadataUniversalIdentifier: POST_CARD_RECIPIENT_UNIVERSAL_IDENTIFIER,
relationTargetFieldMetadataUniversalIdentifier: POST_CARD_FIELD_ID,
universalSettings: {
relationType: RelationType.ONE_TO_MANY,
},
});
Step 2: Define the MANY_TO_ONE side on PostCardRecipient (the “many” side — holds the foreign key):
src/fields/post-card-on-post-card-recipient.field.ts
import { defineField, FieldType, RelationType, OnDeleteAction } from 'twenty-sdk/define';
import { POST_CARD_UNIVERSAL_IDENTIFIER } from '../objects/post-card.object';
import { POST_CARD_RECIPIENT_UNIVERSAL_IDENTIFIER } from '../objects/post-card-recipient.object';
// Export so the other side can reference it
export const POST_CARD_FIELD_ID = 'b2222222-2222-2222-2222-222222222222';
// Import from the other side
import { POST_CARD_RECIPIENTS_FIELD_ID } from './post-card-recipients-on-post-card.field';
export default defineField({
universalIdentifier: POST_CARD_FIELD_ID,
objectUniversalIdentifier: POST_CARD_RECIPIENT_UNIVERSAL_IDENTIFIER,
type: FieldType.RELATION,
name: 'postCard',
label: 'Post Card',
icon: 'IconMail',
relationTargetObjectMetadataUniversalIdentifier: POST_CARD_UNIVERSAL_IDENTIFIER,
relationTargetFieldMetadataUniversalIdentifier: POST_CARD_RECIPIENTS_FIELD_ID,
universalSettings: {
relationType: RelationType.MANY_TO_ONE,
onDelete: OnDeleteAction.CASCADE,
joinColumnName: 'postCardId',
},
});
Circular imports: both relation fields reference each other’s universalIdentifier. To avoid circular import issues, export your field IDs as named constants from each file and import them in the other. The build system resolves these at compile time.
Relating to standard objects
To create a relation with a built-in Twenty object (Person, Company, etc.), use STANDARD_OBJECT_UNIVERSAL_IDENTIFIERS:
src/fields/person-on-self-hosting-user.field.ts
import {
defineField,
FieldType,
RelationType,
OnDeleteAction,
STANDARD_OBJECT_UNIVERSAL_IDENTIFIERS,
} from 'twenty-sdk/define';
import { SELF_HOSTING_USER_UNIVERSAL_IDENTIFIER } from '../objects/self-hosting-user.object';
export const PERSON_FIELD_ID = 'c3333333-3333-3333-3333-333333333333';
export const SELF_HOSTING_USER_REVERSE_FIELD_ID = 'd4444444-4444-4444-4444-444444444444';
export default defineField({
universalIdentifier: PERSON_FIELD_ID,
objectUniversalIdentifier: SELF_HOSTING_USER_UNIVERSAL_IDENTIFIER,
type: FieldType.RELATION,
name: 'person',
label: 'Person',
description: 'Person matching with the self hosting user',
isNullable: true,
relationTargetObjectMetadataUniversalIdentifier:
STANDARD_OBJECT_UNIVERSAL_IDENTIFIERS.person.universalIdentifier,
relationTargetFieldMetadataUniversalIdentifier: SELF_HOSTING_USER_REVERSE_FIELD_ID,
universalSettings: {
relationType: RelationType.MANY_TO_ONE,
onDelete: OnDeleteAction.SET_NULL,
joinColumnName: 'personId',
},
});
Relation field properties
| Property | Required | Description |
|---|
type | Yes | Must be FieldType.RELATION |
relationTargetObjectMetadataUniversalIdentifier | Yes | The universalIdentifier of the target object |
relationTargetFieldMetadataUniversalIdentifier | Yes | The universalIdentifier of the matching field on the target object |
universalSettings.relationType | Yes | RelationType.MANY_TO_ONE or RelationType.ONE_TO_MANY |
universalSettings.onDelete | MANY_TO_ONE only | What happens when the referenced record is deleted: CASCADE, SET_NULL, RESTRICT, or NO_ACTION |
universalSettings.joinColumnName | MANY_TO_ONE only | Database column name for the foreign key (e.g., postCardId) |
Inline relation fields
You can also declare a relation directly inside defineObject. When inline, omit objectUniversalIdentifier — it’s inherited from the parent object:
export default defineObject({
universalIdentifier: '...',
nameSingular: 'postCardRecipient',
// ...
fields: [
{
universalIdentifier: POST_CARD_FIELD_ID,
type: FieldType.RELATION,
name: 'postCard',
label: 'Post Card',
relationTargetObjectMetadataUniversalIdentifier: POST_CARD_UNIVERSAL_IDENTIFIER,
relationTargetFieldMetadataUniversalIdentifier: POST_CARD_RECIPIENTS_FIELD_ID,
universalSettings: {
relationType: RelationType.MANY_TO_ONE,
onDelete: OnDeleteAction.CASCADE,
joinColumnName: 'postCardId',
},
},
// … other fields
],
});