diff --git a/packages/core/database/src/__tests__/associations/references.test.ts b/packages/core/database/src/__tests__/associations/references.test.ts
new file mode 100644
index 000000000..7fe4baabc
--- /dev/null
+++ b/packages/core/database/src/__tests__/associations/references.test.ts
@@ -0,0 +1,52 @@
+import { Database } from '../../database';
+import { mockDatabase } from '../index';
+describe('association references', () => {
+  let db: Database;
+
+  beforeEach(async () => {
+    db = mockDatabase();
+
+    await db.clean({ drop: true });
+  });
+
+  afterEach(async () => {
+    await db.close();
+  });
+
+  it('should add reference with default priority', async () => {
+    const User = db.collection({
+      name: 'users',
+      fields: [{ type: 'hasOne', name: 'profile' }],
+    });
+
+    const Profile = db.collection({
+      name: 'profiles',
+      fields: [{ type: 'belongsTo', name: 'user' }],
+    });
+
+    await db.sync();
+
+    const references = db.referenceMap.getReferences('users');
+
+    expect(references[0].priority).toBe('default');
+  });
+
+  it('should add reference with user defined priority', async () => {
+    const User = db.collection({
+      name: 'users',
+      fields: [{ type: 'hasOne', name: 'profile', onDelete: 'CASCADE' }],
+    });
+
+    const Profile = db.collection({
+      name: 'profiles',
+      fields: [{ type: 'belongsTo', name: 'user' }],
+    });
+
+    await db.sync();
+
+    const references = db.referenceMap.getReferences('users');
+
+    expect(references.length).toBe(1);
+    expect(references[0].priority).toBe('user');
+  });
+});
diff --git a/packages/core/database/src/__tests__/fields/belongs-to-field.test.ts b/packages/core/database/src/__tests__/fields/belongs-to-field.test.ts
index abb81b887..dedcce013 100644
--- a/packages/core/database/src/__tests__/fields/belongs-to-field.test.ts
+++ b/packages/core/database/src/__tests__/fields/belongs-to-field.test.ts
@@ -14,6 +14,36 @@ describe('belongs to field', () => {
     await db.close();
   });
 
+  it('should load with no action', async () => {
+    const User = db.collection({
+      name: 'users',
+      fields: [{ type: 'string', name: 'name', unique: true }],
+    });
+
+    const Post = db.collection({
+      name: 'posts',
+      fields: [
+        { type: 'string', name: 'title' },
+        { type: 'belongsTo', name: 'user', onDelete: 'NO ACTION' },
+      ],
+    });
+
+    await db.sync();
+
+    const u1 = await User.repository.create({ values: { name: 'u1' } });
+    const p1 = await Post.repository.create({ values: { title: 'p1', user: u1.id } });
+
+    // delete u1
+    await User.repository.destroy({ filterByTk: u1.id });
+
+    // list posts with user
+    const post = await Post.repository.findOne({
+      appends: ['user'],
+    });
+
+    expect(post.user).toBeNull();
+  });
+
   it('should throw error when associated with item that null with target key', async () => {
     const User = db.collection({
       name: 'users',
diff --git a/packages/core/database/src/database.ts b/packages/core/database/src/database.ts
index e0726dfdd..106bb8828 100644
--- a/packages/core/database/src/database.ts
+++ b/packages/core/database/src/database.ts
@@ -27,7 +27,7 @@ import { CollectionFactory } from './collection-factory';
 import { CollectionGroupManager } from './collection-group-manager';
 import { ImporterReader, ImportFileExtension } from './collection-importer';
 import DatabaseUtils from './database-utils';
-import ReferencesMap from './features/ReferencesMap';
+import ReferencesMap from './features/references-map';
 import { referentialIntegrityCheck } from './features/referential-integrity-check';
 import { ArrayFieldRepository } from './field-repository/array-field-repository';
 import * as FieldTypes from './fields';
diff --git a/packages/core/database/src/features/ReferencesMap.ts b/packages/core/database/src/features/references-map.ts
similarity index 57%
rename from packages/core/database/src/features/ReferencesMap.ts
rename to packages/core/database/src/features/references-map.ts
index ca4ff7364..a78c6b95c 100644
--- a/packages/core/database/src/features/ReferencesMap.ts
+++ b/packages/core/database/src/features/references-map.ts
@@ -1,30 +1,57 @@
+export type ReferencePriority = 'default' | 'user';
+
 export interface Reference {
   sourceCollectionName: string;
   sourceField: string;
   targetField: string;
   targetCollectionName: string;
   onDelete: string;
+  priority: ReferencePriority;
 }
 
+const DEFAULT_ON_DELETE = 'NO ACTION';
+
+export function buildReference(options: Partial<Reference>): Reference {
+  const { sourceCollectionName, sourceField, targetField, targetCollectionName, onDelete, priority } = options;
+
+  return {
+    sourceCollectionName,
+    sourceField,
+    targetField,
+    targetCollectionName,
+    onDelete: (onDelete || DEFAULT_ON_DELETE).toUpperCase(),
+    priority: assignPriority(priority, onDelete),
+  };
+}
+
+function assignPriority(priority: string | undefined, onDelete: string | undefined): ReferencePriority {
+  if (priority) {
+    return priority as ReferencePriority;
+  }
+
+  return onDelete ? 'user' : 'default';
+}
+
+const PRIORITY_MAP = {
+  default: 1,
+  user: 2,
+};
+
 class ReferencesMap {
   protected map: Map<string, Reference[]> = new Map();
 
   addReference(reference: Reference) {
-    if (!reference.onDelete) {
-      reference.onDelete = 'SET NULL';
-    }
-
-    reference.onDelete = reference.onDelete.toUpperCase();
-
     const existReference = this.existReference(reference);
 
     if (existReference && existReference.onDelete !== reference.onDelete) {
-      if (reference.onDelete === 'SET NULL') {
-        // using existing reference
-        return;
-      } else if (existReference.onDelete === 'SET NULL') {
+      // check two references onDelete priority, using the higher priority, if both are the same, throw error
+      const existPriority = PRIORITY_MAP[existReference.priority];
+      const newPriority = PRIORITY_MAP[reference.priority];
+
+      if (newPriority > existPriority) {
         existReference.onDelete = reference.onDelete;
-      } else {
+        existReference.priority = reference.priority;
+      } else if (newPriority === existPriority && newPriority === PRIORITY_MAP['user']) {
         throw new Error(
           `On Delete Conflict, exist reference ${JSON.stringify(existReference)}, new reference ${JSON.stringify(
             reference,
@@ -52,7 +79,7 @@ class ReferencesMap {
       return null;
     }
 
-    const keys = Object.keys(reference).filter((k) => k !== 'onDelete');
+    const keys = Object.keys(reference).filter((k) => k !== 'onDelete' && k !== 'priority');
 
     return references.find((ref) => keys.every((key) => ref[key] === reference[key]));
   }
diff --git a/packages/core/database/src/features/referential-integrity-check.ts b/packages/core/database/src/features/referential-integrity-check.ts
index b1b1b278e..039806276 100644
--- a/packages/core/database/src/features/referential-integrity-check.ts
+++ b/packages/core/database/src/features/referential-integrity-check.ts
@@ -21,6 +21,11 @@ export async function referentialIntegrityCheck(options: ReferentialIntegrityChe
 
   for (const reference of references) {
     const { sourceCollectionName, sourceField, targetField, onDelete } = reference;
+
+    if (onDelete === 'NO ACTION') {
+      continue;
+    }
+
     const sourceCollection = db.collections.get(sourceCollectionName);
     const sourceRepository = sourceCollection.repository;
 
diff --git a/packages/core/database/src/fields/belongs-to-field.ts b/packages/core/database/src/fields/belongs-to-field.ts
index 38eab8ef9..586607340 100644
--- a/packages/core/database/src/fields/belongs-to-field.ts
+++ b/packages/core/database/src/fields/belongs-to-field.ts
@@ -1,6 +1,6 @@
 import lodash, { omit } from 'lodash';
 import { BelongsToOptions as SequelizeBelongsToOptions, Utils } from 'sequelize';
-import { Reference } from '../features/ReferencesMap';
+import { buildReference, Reference, ReferencePriority } from '../features/references-map';
 import { checkIdentifier } from '../utils';
 import { BaseRelationFieldOptions, RelationField } from './relation-field';
 
@@ -16,20 +16,26 @@ export class BelongsToField extends RelationField {
     return target || Utils.pluralize(name);
   }
 
-  static toReference(db, association, onDelete) {
+  static toReference(db, association, onDelete, priority: ReferencePriority = 'default'): Reference {
     const targetKey = association.targetKey;
 
-    return {
+    return buildReference({
       sourceCollectionName: db.modelCollection.get(association.source).name,
       sourceField: association.foreignKey,
       targetField: targetKey,
       targetCollectionName: db.modelCollection.get(association.target).name,
       onDelete: onDelete,
-    };
+      priority: priority,
+    });
   }
 
   reference(association): Reference {
-    return BelongsToField.toReference(this.database, association, this.options.onDelete);
+    return BelongsToField.toReference(
+      this.database,
+      association,
+      this.options.onDelete,
+      this.options.onDelete ? 'user' : 'default',
+    );
   }
 
   checkAssociationKeys() {
diff --git a/packages/core/database/src/fields/belongs-to-many-field.ts b/packages/core/database/src/fields/belongs-to-many-field.ts
index b69a68e7a..f82d50520 100644
--- a/packages/core/database/src/fields/belongs-to-many-field.ts
+++ b/packages/core/database/src/fields/belongs-to-many-field.ts
@@ -1,7 +1,7 @@
 import { omit } from 'lodash';
 import { AssociationScope, BelongsToManyOptions as SequelizeBelongsToManyOptions, Utils } from 'sequelize';
 import { Collection } from '../collection';
-import { Reference } from '../features/ReferencesMap';
+import { Reference } from '../features/references-map';
 import { checkIdentifier } from '../utils';
 import { BelongsToField } from './belongs-to-field';
 import { MultipleRelationFieldOptions, RelationField } from './relation-field';
@@ -32,6 +32,8 @@ export class BelongsToManyField extends RelationField {
 
     const onDelete = this.options.onDelete || 'CASCADE';
 
+    const priority = this.options.onDelete ? 'user' : 'default';
+
     const targetAssociation = association.toTarget;
 
     if (association.targetKey) {
@@ -45,8 +47,8 @@ export class BelongsToManyField extends RelationField {
     }
 
     return [
-      BelongsToField.toReference(db, targetAssociation, onDelete),
-      BelongsToField.toReference(db, sourceAssociation, onDelete),
+      BelongsToField.toReference(db, targetAssociation, onDelete, priority),
+      BelongsToField.toReference(db, sourceAssociation, onDelete, priority),
     ];
   }
 
@@ -149,10 +151,6 @@ export class BelongsToManyField extends RelationField {
       Object.defineProperty(Through.model, 'isThrough', { value: true });
     }
 
-    if (!this.options.onDelete) {
-      this.options.onDelete = 'CASCADE';
-    }
-
     const belongsToManyOptions = {
       constraints: false,
       ...omit(this.options, ['name', 'type', 'target']),
diff --git a/packages/core/database/src/fields/has-many-field.ts b/packages/core/database/src/fields/has-many-field.ts
index f266af9f6..28a3f038b 100644
--- a/packages/core/database/src/fields/has-many-field.ts
+++ b/packages/core/database/src/fields/has-many-field.ts
@@ -8,7 +8,7 @@ import {
   Utils,
 } from 'sequelize';
 import { Collection } from '../collection';
-import { Reference } from '../features/ReferencesMap';
+import { buildReference, Reference } from '../features/references-map';
 import { checkIdentifier } from '../utils';
 import { MultipleRelationFieldOptions, RelationField } from './relation-field';
 
@@ -89,13 +89,13 @@ export class HasManyField extends RelationField {
   reference(association): Reference {
     const sourceKey = association.sourceKey;
 
-    return {
+    return buildReference({
       sourceCollectionName: this.database.modelCollection.get(association.target).name,
       sourceField: association.foreignKey,
       targetField: sourceKey,
       targetCollectionName: this.database.modelCollection.get(association.source).name,
       onDelete: this.options.onDelete,
-    };
+    });
   }
 
   checkAssociationKeys() {
diff --git a/packages/core/database/src/fields/has-one-field.ts b/packages/core/database/src/fields/has-one-field.ts
index b6ef32c1f..f2673daca 100644
--- a/packages/core/database/src/fields/has-one-field.ts
+++ b/packages/core/database/src/fields/has-one-field.ts
@@ -8,7 +8,7 @@ import {
   Utils,
 } from 'sequelize';
 import { Collection } from '../collection';
-import { Reference } from '../features/ReferencesMap';
+import { buildReference, Reference } from '../features/references-map';
 import { checkIdentifier } from '../utils';
 import { BaseRelationFieldOptions, RelationField } from './relation-field';
 
@@ -98,13 +98,13 @@ export class HasOneField extends RelationField {
   reference(association): Reference {
     const sourceKey = association.sourceKey;
 
-    return {
+    return buildReference({
       sourceCollectionName: this.database.modelCollection.get(association.target).name,
       sourceField: association.foreignKey,
       targetField: sourceKey,
       targetCollectionName: this.database.modelCollection.get(association.source).name,
       onDelete: this.options.onDelete,
-    };
+    });
   }
 
   checkAssociationKeys() {