feat: implement generic many-to-many junction relation support (#16820)

## Overview This PR implements **generic many-to-many relation support** through junction tables (also known as associative entities or join tables). This replaces the need for hardcoded taskTarget/noteTarget logic and provides a flexible foundation for modeling complex entity relationships. ## Architecture ### Data Model Many-to-many relationships are implemented using a **junction object pattern**: ``` ┌─────────┐ ┌──────────────────┐ ┌─────────┐ │ Pet │──────>│ PetRocket │<──────│ Rocket │ │ │ 1:N │ (junction) │ N:1 │ │ │ rockets ├───────┤ pet : Pet ├───────┤ │ └─────────┘ │ rocket : Rocket │ └─────────┘ └──────────────────┘ ``` The junction object (PetRocket) has: - A `MANY_TO_ONE` relation to **Pet** (the source) - A `MANY_TO_ONE` relation to **Rocket** (the target) The source object (Pet) has a `ONE_TO_MANY` relation pointing to the junction, with **field settings** that specify which target field to follow. ### Field Settings Schema Junction configuration is stored in `FieldMetadataRelationSettings`: ```typescript { relationType: "ONE_TO_MANY", // Points to the target field on the junction object junctionTargetFieldId?: string; // For regular relations junctionTargetMorphId?: string; // For polymorphic relations } ``` **Two configuration modes:** 1. **`junctionTargetFieldId`** - References a specific `RELATION` field on the junction 2. **`junctionTargetMorphId`** - References a `morphId` group for polymorphic targets (e.g., link to Person OR Company) ### GraphQL Query Generation When a junction relation is detected, the GraphQL fields are generated to fetch the nested target: ```graphql query GetPetWithRockets { pet(id: "...") { rockets { # ONE_TO_MANY to junction id rocket { # Target field on junction id name __typename } } } } ``` For polymorphic junction targets: ```graphql caretakerPerson { id, name } caretakerCompany { id, name } ``` ## Frontend Architecture ### Display Flow 1. **Detection**: `hasJunctionConfig()` checks if field has junction settings 2. **Config Resolution**: `getJunctionConfig()` resolves junction object metadata and target fields 3. **Record Extraction**: `extractTargetRecordsFromJunction()` extracts target records from junction records 4. **Rendering**: Target records displayed as chips (not junction records) ### Edit Flow 1. **Picker Opening**: Initializes the multi-record picker with: - Searchable object types (derived from junction target fields) - Pre-selected items (extracted from existing junction records) 2. **Selection Handling**: Manages create/delete of junction records: - **Select**: Creates new junction record with source + target IDs - **Deselect**: Finds and deletes the junction record - **Optimistic Updates**: Manually updates Recoil store before API call ### Key Trade-offs | Decision | Trade-off | |----------|-----------| | Junction records managed manually | More control over optimistic updates, but requires manual cache management | | Settings stored per-field | Flexible (same junction can power different views), but requires UI to configure | | Polymorphic via morphId groups | Supports N target types, but adds query complexity | | Feature flag gated | Safe rollout, but requires flag management | ## Backend Changes - **Validation**: Junction target field must exist and be a valid `MANY_TO_ONE` relation - **Settings**: Extended `FieldMetadataRelationSettings` type with junction fields - **Dev Seeder**: Added sample junction objects (PetRocket, EmploymentHistory, PetCareAgreement) for testing ## How to Test 1. Enable the `IS_JUNCTION_RELATIONS_ENABLED` feature flag 2. Create objects with junction pattern (Pet → PetRocket → Rocket) 3. Configure the junction target in field settings (advanced mode) 4. Verify: - Display shows target objects (Rockets), not junction records (PetRockets) - Picker allows selecting/deselecting targets - Changes persist correctly https://github.com/user-attachments/assets/d04f057a-228c-4de8-af48-76bb2d72cac1 --------- Co-authored-by: Charles Bochet <charles@twenty.com>
2026-01-20 21:58:13 +01:00
parent 0e7e471312
commit 3ed67b825e
102 changed files with 3895 additions and 476 deletions
@@ -76,6 +76,11 @@ export const seedFeatureFlags = async ({
        workspaceId: workspaceId,
        value: true,
      },
+      {
+        key: FeatureFlagKey.IS_JUNCTION_RELATIONS_ENABLED,
+        workspaceId: workspaceId,
+        value: true,
+      },
      {
        key: FeatureFlagKey.IS_SSE_DB_EVENTS_ENABLED,
        workspaceId: workspaceId,
@@ -0,0 +1,53 @@
+import { COMPANY_DATA_SEED_IDS } from 'src/engine/workspace-manager/dev-seeder/data/constants/company-data-seeds.constant';
+import { PERSON_DATA_SEED_IDS } from 'src/engine/workspace-manager/dev-seeder/data/constants/person-data-seeds.constant';
+
+type EmploymentHistoryDataSeed = {
+  id: string;
+  personId: string;
+  companyId: string;
+};
+
+export const EMPLOYMENT_HISTORY_DATA_SEED_COLUMNS: (keyof EmploymentHistoryDataSeed)[] =
+  ['id', 'personId', 'companyId'];
+
+export const EMPLOYMENT_HISTORY_DATA_SEED_IDS = {
+  ID_1: '20202020-e001-4000-8000-000000000001',
+  ID_2: '20202020-e001-4000-8000-000000000002',
+  ID_3: '20202020-e001-4000-8000-000000000003',
+  ID_4: '20202020-e001-4000-8000-000000000004',
+  ID_5: '20202020-e001-4000-8000-000000000005',
+};
+
+// Sample employment histories: some people have worked at different companies
+export const EMPLOYMENT_HISTORY_DATA_SEEDS: EmploymentHistoryDataSeed[] = [
+  // Mark Young (Person 1) previously worked at Company 2
+  {
+    id: EMPLOYMENT_HISTORY_DATA_SEED_IDS.ID_1,
+    personId: PERSON_DATA_SEED_IDS.ID_1,
+    companyId: COMPANY_DATA_SEED_IDS.ID_2,
+  },
+  // Mark Young (Person 1) also previously worked at Company 3
+  {
+    id: EMPLOYMENT_HISTORY_DATA_SEED_IDS.ID_2,
+    personId: PERSON_DATA_SEED_IDS.ID_1,
+    companyId: COMPANY_DATA_SEED_IDS.ID_3,
+  },
+  // Gabriel Robinson (Person 2) previously worked at Company 4
+  {
+    id: EMPLOYMENT_HISTORY_DATA_SEED_IDS.ID_3,
+    personId: PERSON_DATA_SEED_IDS.ID_2,
+    companyId: COMPANY_DATA_SEED_IDS.ID_4,
+  },
+  // Kimberly Gordon (Person 3) previously worked at Company 1
+  {
+    id: EMPLOYMENT_HISTORY_DATA_SEED_IDS.ID_4,
+    personId: PERSON_DATA_SEED_IDS.ID_3,
+    companyId: COMPANY_DATA_SEED_IDS.ID_1,
+  },
+  // Cindy Baker (Person 4) previously worked at Company 5
+  {
+    id: EMPLOYMENT_HISTORY_DATA_SEED_IDS.ID_5,
+    personId: PERSON_DATA_SEED_IDS.ID_4,
+    companyId: COMPANY_DATA_SEED_IDS.ID_5,
+  },
+];
@@ -0,0 +1,45 @@
+import { COMPANY_DATA_SEED_IDS } from 'src/engine/workspace-manager/dev-seeder/data/constants/company-data-seeds.constant';
+import { PERSON_DATA_SEED_IDS } from 'src/engine/workspace-manager/dev-seeder/data/constants/person-data-seeds.constant';
+import { PET_DATA_SEED_IDS } from 'src/engine/workspace-manager/dev-seeder/data/constants/pet-data-seeds.constant';
+
+type PetCareAgreementDataSeed = {
+  id: string;
+  petId: string;
+  // Morph relation creates separate columns for each target type
+  caretakerPersonId: string | null;
+  caretakerCompanyId: string | null;
+};
+
+export const PET_CARE_AGREEMENT_DATA_SEED_COLUMNS: (keyof PetCareAgreementDataSeed)[] =
+  ['id', 'petId', 'caretakerPersonId', 'caretakerCompanyId'];
+
+export const PET_CARE_AGREEMENT_DATA_SEED_IDS = {
+  ID_1: '20202020-c001-4000-8000-000000000001',
+  ID_2: '20202020-c001-4000-8000-000000000002',
+  ID_3: '20202020-c001-4000-8000-000000000003',
+};
+
+// Sample pet care agreements: Toby the pet has multiple caretakers (both persons and companies)
+export const PET_CARE_AGREEMENT_DATA_SEEDS: PetCareAgreementDataSeed[] = [
+  // Toby is cared for by Mark Young (Person 1)
+  {
+    id: PET_CARE_AGREEMENT_DATA_SEED_IDS.ID_1,
+    petId: PET_DATA_SEED_IDS.ID_1,
+    caretakerPersonId: PERSON_DATA_SEED_IDS.ID_1,
+    caretakerCompanyId: null,
+  },
+  // Toby is also cared for by Gabriel Robinson (Person 2)
+  {
+    id: PET_CARE_AGREEMENT_DATA_SEED_IDS.ID_2,
+    petId: PET_DATA_SEED_IDS.ID_1,
+    caretakerPersonId: PERSON_DATA_SEED_IDS.ID_2,
+    caretakerCompanyId: null,
+  },
+  // Toby is also cared for by Company 1 (a pet care service company)
+  {
+    id: PET_CARE_AGREEMENT_DATA_SEED_IDS.ID_3,
+    petId: PET_DATA_SEED_IDS.ID_1,
+    caretakerPersonId: null,
+    caretakerCompanyId: COMPANY_DATA_SEED_IDS.ID_1,
+  },
+];
@@ -45,6 +45,10 @@ import {
  DASHBOARD_DATA_SEED_COLUMNS,
  getDashboardDataSeeds,
 } from 'src/engine/workspace-manager/dev-seeder/data/constants/dashboard-data-seeds.constant';
+import {
+  EMPLOYMENT_HISTORY_DATA_SEED_COLUMNS,
+  EMPLOYMENT_HISTORY_DATA_SEEDS,
+} from 'src/engine/workspace-manager/dev-seeder/data/constants/employment-history-data-seeds.constant';
 import {
  MESSAGE_CHANNEL_DATA_SEED_COLUMNS,
  MESSAGE_CHANNEL_DATA_SEEDS,
@@ -81,6 +85,10 @@ import {
  PERSON_DATA_SEED_COLUMNS,
  PERSON_DATA_SEEDS,
 } from 'src/engine/workspace-manager/dev-seeder/data/constants/person-data-seeds.constant';
+import {
+  PET_CARE_AGREEMENT_DATA_SEED_COLUMNS,
+  PET_CARE_AGREEMENT_DATA_SEEDS,
+} from 'src/engine/workspace-manager/dev-seeder/data/constants/pet-care-agreement-data-seeds.constant';
 import {
  PET_DATA_SEED_COLUMNS,
  PET_DATA_SEEDS,
@@ -208,6 +216,17 @@ const getRecordSeedsBatches = (
      pgColumns: MESSAGE_THREAD_DATA_SEED_COLUMNS,
      recordSeeds: MESSAGE_THREAD_DATA_SEEDS,
    },
+    // Junction tables
+    {
+      tableName: '_employmentHistory',
+      pgColumns: EMPLOYMENT_HISTORY_DATA_SEED_COLUMNS,
+      recordSeeds: EMPLOYMENT_HISTORY_DATA_SEEDS,
+    },
+    {
+      tableName: '_petCareAgreement',
+      pgColumns: PET_CARE_AGREEMENT_DATA_SEED_COLUMNS,
+      recordSeeds: PET_CARE_AGREEMENT_DATA_SEEDS,
+    },
  ];

  // Batch 5: Depends on batch 4 entities
@@ -0,0 +1,25 @@
+import { FieldMetadataType, RelationType } from 'twenty-shared/types';
+
+import { type FieldMetadataSeed } from 'src/engine/workspace-manager/dev-seeder/metadata/types/field-metadata-seed.type';
+
+// Note: The `pet` relation is created automatically when the junction field
+// `caretakers` is created on Pet (as the inverse side)
+
+// Morph relation to caretaker (Person or Company)
+export const PET_CARE_AGREEMENT_CARETAKER_MORPH_SEED: FieldMetadataSeed & {
+  targetObjectMetadataNames: string[];
+} = {
+  type: FieldMetadataType.MORPH_RELATION,
+  label: 'Caretaker',
+  name: 'caretaker',
+  icon: 'IconUser',
+  morphRelationsCreationPayload: [
+    {
+      type: RelationType.MANY_TO_ONE,
+      targetObjectMetadataId: 'to-be-resolved-later',
+      targetFieldLabel: 'Cared For Pets',
+      targetFieldIcon: 'IconPaw',
+    },
+  ],
+  targetObjectMetadataNames: ['person', 'company'],
+};
@@ -8,14 +8,14 @@ export const PET_CUSTOM_RELATION_FIELD_SEEDS: (FieldMetadataSeed & {
 })[] = [
  {
    type: FieldMetadataType.MORPH_RELATION,
-    label: 'Owner of the Pet (rocket or survey)',
-    name: 'owner',
+    label: 'Polymorphic Owner',
+    name: 'polymorphicOwner',
    icon: 'IconRelationManyToOne',
    morphRelationsCreationPayload: [
      {
        type: RelationType.MANY_TO_ONE,
        targetObjectMetadataId: 'to-be-resolved-later',
-        targetFieldLabel: 'Owned by',
+        targetFieldLabel: 'Owned Pets',
        targetFieldIcon: 'IconRelationOneToMany',
      },
    ],
@@ -26,14 +26,14 @@ export const PET_CUSTOM_RELATION_FIELD_SEEDS: (FieldMetadataSeed & {
  },
  {
    type: FieldMetadataType.MORPH_RELATION,
-    label: 'Helper of the Pet (rocket or survey)',
-    name: 'helper',
+    label: 'Polymorphic Helper',
+    name: 'polymorphicHelper',
    icon: 'IconRelationOneToMany',
    morphRelationsCreationPayload: [
      {
        type: RelationType.ONE_TO_MANY,
        targetObjectMetadataId: 'to-be-resolved-later',
-        targetFieldLabel: 'Helped by',
+        targetFieldLabel: 'Helped Pets',
        targetFieldIcon: 'IconRelationOneToMany',
      },
    ],
@@ -0,0 +1,10 @@
+import { type ObjectMetadataSeed } from 'src/engine/workspace-manager/dev-seeder/metadata/types/object-metadata-seed.type';
+
+export const EMPLOYMENT_HISTORY_CUSTOM_OBJECT_SEED: ObjectMetadataSeed = {
+  labelPlural: 'Employment Histories',
+  labelSingular: 'Employment History',
+  namePlural: 'employmentHistories',
+  nameSingular: 'employmentHistory',
+  icon: 'IconBriefcase',
+  skipNameField: true,
+};
@@ -0,0 +1,10 @@
+import { type ObjectMetadataSeed } from 'src/engine/workspace-manager/dev-seeder/metadata/types/object-metadata-seed.type';
+
+export const PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED: ObjectMetadataSeed = {
+  labelPlural: 'Pet Care Agreements',
+  labelSingular: 'Pet Care Agreement',
+  namePlural: 'petCareAgreements',
+  nameSingular: 'petCareAgreement',
+  icon: 'IconPaw',
+  skipNameField: true,
+};
@@ -1,9 +1,9 @@
 import { Injectable } from '@nestjs/common';

+import { FieldMetadataType, RelationType } from 'twenty-shared/types';
 import { isDefined } from 'twenty-shared/utils';

 import { type DataSourceEntity } from 'src/engine/metadata-modules/data-source/data-source.entity';
-import { CreateFieldInput } from 'src/engine/metadata-modules/field-metadata/dtos/create-field.input';
 import { FieldMetadataService } from 'src/engine/metadata-modules/field-metadata/services/field-metadata.service';
 import { WorkspaceManyOrAllFlatEntityMapsCacheService } from 'src/engine/metadata-modules/flat-entity/services/workspace-many-or-all-flat-entity-maps-cache.service';
 import { buildObjectIdByNameMaps } from 'src/engine/metadata-modules/flat-object-metadata/utils/build-object-id-by-name-maps.util';
@@ -14,15 +14,46 @@ import {
 } from 'src/engine/workspace-manager/dev-seeder/core/constants/seeder-workspaces.constant';
 import { COMPANY_CUSTOM_FIELD_SEEDS } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/company-custom-field-seeds.constant';
 import { PERSON_CUSTOM_FIELD_SEEDS } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/person-custom-field-seeds.constant';
+import { PET_CARE_AGREEMENT_CARETAKER_MORPH_SEED } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/pet-care-agreement-custom-relation-field-seeds.constant';
 import { PET_CUSTOM_FIELD_SEEDS } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/pet-custom-field-seeds.constant';
 import { PET_CUSTOM_RELATION_FIELD_SEEDS } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/pet-custom-relation-field-seeds.constant';
 import { SURVEY_RESULT_CUSTOM_FIELD_SEEDS } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/survey-results-field-seeds.constant';
+import { EMPLOYMENT_HISTORY_CUSTOM_OBJECT_SEED } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-objects/constants/employment-history-custom-object-seed.constant';
+import { PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-objects/constants/pet-care-agreement-custom-object-seed.constant';
 import { PET_CUSTOM_OBJECT_SEED } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-objects/constants/pet-custom-object-seed.constant';
 import { ROCKET_CUSTOM_OBJECT_SEED } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-objects/constants/rocket-custom-object-seed.constant';
 import { SURVEY_RESULT_CUSTOM_OBJECT_SEED } from 'src/engine/workspace-manager/dev-seeder/metadata/custom-objects/constants/survey-results-object-seed.constant';
 import { type FieldMetadataSeed } from 'src/engine/workspace-manager/dev-seeder/metadata/types/field-metadata-seed.type';
 import { type ObjectMetadataSeed } from 'src/engine/workspace-manager/dev-seeder/metadata/types/object-metadata-seed.type';

+type MorphRelationSeed = FieldMetadataSeed & {
+  targetObjectMetadataNames: string[];
+};
+
+type JunctionFieldSeed = {
+  sourceObjectName: string;
+  name: string;
+  label: string;
+  icon: string;
+  targetObjectName: string;
+  targetFieldLabel: string;
+  targetFieldIcon: string;
+};
+
+type JunctionConfigSeed = {
+  objectName: string;
+  fieldName: string;
+  junctionTargetFieldRef: string;
+  label?: string;
+};
+
+// Helper type for flat entity maps
+type FlatMaps = {
+  fieldMaps: { byId: Record<string, { name: string; morphId?: string }> };
+  objectMaps: { byId: Record<string, { fieldMetadataIds: string[] }> };
+  objectIdByName: Record<string, string>;
+};
+
@Injectable()
 export class DevSeederMetadataService {
  constructor(
@@ -36,10 +67,11 @@ export class DevSeederMetadataService {
    {
      objects: { seed: ObjectMetadataSeed; fields?: FieldMetadataSeed[] }[];
      fields: { objectName: string; seeds: FieldMetadataSeed[] }[];
-      relations?: {
-        objectName: string;
-        seeds: (FieldMetadataSeed & { targetObjectMetadataNames: string[] })[];
-      }[];
+      morphRelations?: { objectName: string; seeds: MorphRelationSeed[] }[];
+      // Junction fields create relations to junction objects (inverses auto-created)
+      junctionFields?: JunctionFieldSeed[];
+      // Configure junction settings on fields after all relations exist
+      junctionConfigs?: JunctionConfigSeed[];
    }
  > = {
    [SEED_APPLE_WORKSPACE_ID]: {
@@ -50,16 +82,83 @@ export class DevSeederMetadataService {
          seed: SURVEY_RESULT_CUSTOM_OBJECT_SEED,
          fields: SURVEY_RESULT_CUSTOM_FIELD_SEEDS,
        },
+        // Junction objects (minimal pivots)
+        { seed: EMPLOYMENT_HISTORY_CUSTOM_OBJECT_SEED },
+        { seed: PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED },
      ],
      fields: [
        { objectName: 'company', seeds: COMPANY_CUSTOM_FIELD_SEEDS },
        { objectName: 'person', seeds: PERSON_CUSTOM_FIELD_SEEDS },
      ],
-      relations: [
+      morphRelations: [
        {
          objectName: PET_CUSTOM_OBJECT_SEED.nameSingular,
          seeds: PET_CUSTOM_RELATION_FIELD_SEEDS,
        },
+        {
+          objectName: PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED.nameSingular,
+          seeds: [PET_CARE_AGREEMENT_CARETAKER_MORPH_SEED],
+        },
+      ],
+      junctionFields: [
+        // Employment History: Person <-> Company
+        {
+          sourceObjectName: 'person',
+          name: 'previousCompanies',
+          label: 'Previous Companies',
+          icon: 'IconBuildingSkyscraper',
+          targetObjectName: EMPLOYMENT_HISTORY_CUSTOM_OBJECT_SEED.nameSingular,
+          targetFieldLabel: 'Person',
+          targetFieldIcon: 'IconUser',
+        },
+        {
+          sourceObjectName: 'company',
+          name: 'previousEmployees',
+          label: 'Previous Employees',
+          icon: 'IconUser',
+          targetObjectName: EMPLOYMENT_HISTORY_CUSTOM_OBJECT_SEED.nameSingular,
+          targetFieldLabel: 'Company',
+          targetFieldIcon: 'IconBuildingSkyscraper',
+        },
+        // Pet Care Agreement: Pet -> caretakers
+        {
+          sourceObjectName: PET_CUSTOM_OBJECT_SEED.nameSingular,
+          name: 'caretakers',
+          label: 'Caretakers',
+          icon: 'IconUser',
+          targetObjectName: PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED.nameSingular,
+          targetFieldLabel: 'Pet',
+          targetFieldIcon: 'IconCat',
+        },
+      ],
+      junctionConfigs: [
+        // Employment History junction configs
+        {
+          objectName: 'person',
+          fieldName: 'previousCompanies',
+          junctionTargetFieldRef: `${EMPLOYMENT_HISTORY_CUSTOM_OBJECT_SEED.nameSingular}.company`,
+        },
+        {
+          objectName: 'company',
+          fieldName: 'previousEmployees',
+          junctionTargetFieldRef: `${EMPLOYMENT_HISTORY_CUSTOM_OBJECT_SEED.nameSingular}.person`,
+        },
+        // Pet Care Agreement junction configs
+        {
+          objectName: PET_CUSTOM_OBJECT_SEED.nameSingular,
+          fieldName: 'caretakers',
+          junctionTargetFieldRef: `${PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED.nameSingular}.caretakerPerson`,
+        },
+        {
+          objectName: 'company',
+          fieldName: 'caredForPets',
+          junctionTargetFieldRef: `${PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED.nameSingular}.pet`,
+        },
+        {
+          objectName: 'person',
+          fieldName: 'caredForPets',
+          junctionTargetFieldRef: `${PET_CARE_AGREEMENT_CUSTOM_OBJECT_SEED.nameSingular}.pet`,
+        },
      ],
    },
    [SEED_YCOMBINATOR_WORKSPACE_ID]: {
@@ -91,7 +190,6 @@ export class DevSeederMetadataService {
      );
    }

-    // TODO get
    for (const obj of config.objects) {
      await this.seedCustomObject({
        dataSourceId: dataSourceMetadata.id,
@@ -174,60 +272,113 @@ export class DevSeederMetadataService {
      );
    }

-    if (!config.relations) {
-      return;
-    }
+    // 1. Seed morph relations (creates inverses on target objects)
+    let maps = await this.getFreshFlatMaps(workspaceId);

-    for (const relation of config.relations) {
-      await this.seedCustomRelation({
+    for (const relation of config.morphRelations ?? []) {
+      await this.seedMorphRelations({
        workspaceId,
        relation,
+        objectIdByNameSingular: maps.objectIdByName,
      });
    }
+
+    // 2. Seed junction fields (creates relations + inverses on junction objects)
+    // Use same maps for all - matches original working behavior
+    maps = await this.getFreshFlatMaps(workspaceId);
+
+    for (const field of config.junctionFields ?? []) {
+      await this.seedJunctionField({ workspaceId, field, flatMaps: maps });
+    }
+
+    // 3. Configure junction settings (after all fields exist)
+    if (config.junctionConfigs && config.junctionConfigs.length > 0) {
+      maps = await this.getFreshFlatMaps(workspaceId);
+
+      for (const junctionConfig of config.junctionConfigs) {
+        await this.applyJunctionConfig({
+          workspaceId,
+          junctionConfig,
+          flatMaps: maps,
+        });
+      }
+    }
  }

-  private async seedCustomRelation({
+  private async getFreshFlatMaps(workspaceId: string): Promise<FlatMaps> {
+    await this.flatEntityMapsCacheService.invalidateFlatEntityMaps({
+      workspaceId,
+      flatMapsKeys: ['flatObjectMetadataMaps', 'flatFieldMetadataMaps'],
+    });
+
+    const { flatObjectMetadataMaps, flatFieldMetadataMaps } =
+      await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
+        {
+          workspaceId,
+          flatMapsKeys: ['flatObjectMetadataMaps', 'flatFieldMetadataMaps'],
+        },
+      );
+
+    const { idByNameSingular } = buildObjectIdByNameMaps(
+      flatObjectMetadataMaps,
+    );
+
+    return {
+      fieldMaps: flatFieldMetadataMaps as FlatMaps['fieldMaps'],
+      objectMaps: flatObjectMetadataMaps as FlatMaps['objectMaps'],
+      objectIdByName: idByNameSingular,
+    };
+  }
+
+  private async applyJunctionConfig({
+    workspaceId,
+    junctionConfig,
+    flatMaps,
+  }: {
+    workspaceId: string;
+    junctionConfig: JunctionConfigSeed;
+    flatMaps: FlatMaps;
+  }): Promise<void> {
+    const [targetObjectName, targetFieldName] =
+      junctionConfig.junctionTargetFieldRef.split('.');
+
+    const junctionTargetFieldId = this.findFieldId(
+      targetObjectName,
+      targetFieldName,
+      flatMaps,
+    );
+
+    const fieldId = this.findFieldId(
+      junctionConfig.objectName,
+      junctionConfig.fieldName,
+      flatMaps,
+    );
+
+    await this.fieldMetadataService.updateOneField({
+      workspaceId,
+      updateFieldInput: {
+        id: fieldId,
+        ...(junctionConfig.label && { label: junctionConfig.label }),
+        settings: {
+          relationType: RelationType.ONE_TO_MANY,
+          junctionTargetFieldId,
+        },
+      },
+    });
+  }
+
+  private async seedMorphRelations({
    workspaceId,
    relation,
+    objectIdByNameSingular,
  }: {
    workspaceId: string;
    relation: {
      objectName: string;
-      seeds: (FieldMetadataSeed & { targetObjectMetadataNames: string[] })[];
-    };
-  }): Promise<void> {
-    const { flatObjectMetadataMaps } =
-      await this.flatEntityMapsCacheService.getOrRecomputeManyOrAllFlatEntityMaps(
-        {
-          workspaceId,
-          flatMapsKeys: ['flatObjectMetadataMaps'],
-        },
-      );
-
-    const { idByNameSingular: objectIdByNameSingular } =
-      buildObjectIdByNameMaps(flatObjectMetadataMaps);
-
-    const createFieldInputs = this.createFieldInputs({
-      relation,
-      objectIdByNameSingular,
-    });
-
-    await this.fieldMetadataService.createManyFields({
-      createFieldInputs,
-      workspaceId,
-    });
-  }
-
-  private createFieldInputs({
-    relation,
-    objectIdByNameSingular,
-  }: {
-    relation: {
-      objectName: string;
-      seeds: (FieldMetadataSeed & { targetObjectMetadataNames: string[] })[];
+      seeds: MorphRelationSeed[];
    };
    objectIdByNameSingular: Record<string, string>;
-  }): Omit<CreateFieldInput, 'workspaceId'>[] {
+  }): Promise<void> {
    const objectMetadataId = objectIdByNameSingular[relation.objectName];

    if (!isDefined(objectMetadataId)) {
@@ -236,10 +387,11 @@ export class DevSeederMetadataService {
      );
    }

-    const relationFieldInputs = relation.seeds.map((seed) => ({
+    const createFieldInputs = relation.seeds.map((seed) => ({
      type: seed.type,
      label: seed.label,
      name: seed.name,
+      icon: seed.icon,
      objectMetadataId,
      morphRelationsCreationPayload: seed.targetObjectMetadataNames.map(
        (targetObjectMetadataName) => {
@@ -268,6 +420,74 @@ export class DevSeederMetadataService {
      ),
    }));

-    return relationFieldInputs;
+    await this.fieldMetadataService.createManyFields({
+      createFieldInputs,
+      workspaceId,
+    });
+  }
+
+  private async seedJunctionField({
+    workspaceId,
+    field,
+    flatMaps,
+  }: {
+    workspaceId: string;
+    field: JunctionFieldSeed;
+    flatMaps: FlatMaps;
+  }): Promise<void> {
+    const sourceObjectId = flatMaps.objectIdByName[field.sourceObjectName];
+    const targetObjectId = flatMaps.objectIdByName[field.targetObjectName];
+
+    if (!isDefined(sourceObjectId)) {
+      throw new Error(`Source object not found: ${field.sourceObjectName}`);
+    }
+    if (!isDefined(targetObjectId)) {
+      throw new Error(`Target object not found: ${field.targetObjectName}`);
+    }
+
+    await this.fieldMetadataService.createManyFields({
+      createFieldInputs: [
+        {
+          type: FieldMetadataType.RELATION,
+          name: field.name,
+          label: field.label,
+          icon: field.icon,
+          objectMetadataId: sourceObjectId,
+          relationCreationPayload: {
+            type: RelationType.ONE_TO_MANY,
+            targetFieldLabel: field.targetFieldLabel,
+            targetFieldIcon: field.targetFieldIcon,
+            targetObjectMetadataId: targetObjectId,
+          },
+        },
+      ],
+      workspaceId,
+    });
+  }
+
+  private findFieldId(
+    objectName: string,
+    fieldName: string,
+    flatMaps: FlatMaps,
+  ): string {
+    const objectId = flatMaps.objectIdByName[objectName];
+
+    if (!isDefined(objectId)) {
+      throw new Error(`Object not found: ${objectName}`);
+    }
+
+    const objectMetadata = flatMaps.objectMaps.byId[objectId];
+
+    if (!isDefined(objectMetadata)) {
+      throw new Error(`Object metadata not found: ${objectName}`);
+    }
+
+    for (const fieldId of objectMetadata.fieldMetadataIds) {
+      if (flatMaps.fieldMaps.byId[fieldId]?.name === fieldName) {
+        return fieldId;
+      }
+    }
+
+    throw new Error(`Field not found: ${objectName}.${fieldName}`);
  }
 }
@@ -3,4 +3,6 @@ import { type CreateObjectInput } from 'src/engine/metadata-modules/object-metad
 export type ObjectMetadataSeed = Omit<
  CreateObjectInput,
  'workspaceId' | 'dataSourceId' | 'fields'
->;
+> & {
+  skipNameField?: boolean;
+};