diff --git a/application/Espo/ORM/BaseEntity.php b/application/Espo/ORM/BaseEntity.php
index f724dbc706..c0f538b1d8 100644
--- a/application/Espo/ORM/BaseEntity.php
+++ b/application/Espo/ORM/BaseEntity.php
@@ -255,8 +255,14 @@ class BaseEntity implements Entity
             );
         }
 
-        // @todo Remove $this->id check when relation setting is implemented.
+        // @todo Remove support in v10.0.
         if ($this->hasRelation($attribute) && $this->id && !$params) {
+            trigger_error(
+                "Accessing related records with Entity::get is deprecated. " .
+                "Use `\$entityManager->getRelation(...)->find()`.",
+                E_USER_DEPRECATED
+            );
+
             $isMany = in_array($this->getRelationType($attribute), [
                 RelationType::MANY_MANY,
                 RelationType::HAS_MANY,
@@ -268,9 +274,14 @@ class BaseEntity implements Entity
                 $this->relations->getOne($attribute);
         }
 
-        // @todo Revise. Remove?
         // @todo Remove support in v10.0.
         if ($this->hasRelation($attribute) && $this->id && $this->entityManager) {
+            trigger_error(
+                "Accessing related records with Entity::get is deprecated. " .
+                "Use `\$entityManager->getRelation(...)->find()`.",
+                E_USER_DEPRECATED
+            );
+
             /** @phpstan-ignore-next-line */
             return $this->entityManager
                 ->getRepository($this->getEntityType())
diff --git a/application/Espo/ORM/Relation/RDBRelations.php b/application/Espo/ORM/Relation/RDBRelations.php
index d2453e2a4c..5a4d810f31 100644
--- a/application/Espo/ORM/Relation/RDBRelations.php
+++ b/application/Espo/ORM/Relation/RDBRelations.php
@@ -101,8 +101,6 @@ class RDBRelations implements Relations
                 throw new LogicException("No entity set.");
             }
 
-            $relationRepository = $this->entityManager->getRelation($this->entity, $relation);
-
             $isMany = in_array($this->getRelationType($relation), [
                 RelationType::MANY_MANY,
                 RelationType::HAS_MANY,
@@ -111,7 +109,7 @@ class RDBRelations implements Relations
 
             $this->data[$relation] = $isMany ?
                 $this->findMany($relation) :
-                $relationRepository->findOne();
+                $this->findOne($relation);
         }
 
         $object = $this->data[$relation];
@@ -124,6 +122,21 @@ class RDBRelations implements Relations
         return $object;
     }
 
+    private function findOne(string $relation): ?Entity
+    {
+        if (!$this->entity) {
+            throw new LogicException();
+        }
+
+        if (!$this->entity->hasId()) {
+            return null;
+        }
+
+        return $this->entityManager
+            ->getRelation($this->entity, $relation)
+            ->findOne();
+    }
+
     /**
      * @return EntityCollection<Entity>
      */
@@ -133,6 +146,11 @@ class RDBRelations implements Relations
             throw new LogicException();
         }
 
+        if (!$this->entity->hasId()) {
+            /** @var EntityCollection<Entity> */
+            return new EntityCollection();
+        }
+
         $relationDefs = $this->entityManager
             ->getDefs()
             ->getEntity($this->entity->getEntityType())
diff --git a/tests/integration/Espo/ORM/RelationsTest.php b/tests/integration/Espo/ORM/RelationsTest.php
index 543a623473..cb92d3207f 100644
--- a/tests/integration/Espo/ORM/RelationsTest.php
+++ b/tests/integration/Espo/ORM/RelationsTest.php
@@ -33,26 +33,42 @@ use Espo\ORM\EntityCollection;
 use Espo\Modules\Crm\Entities\Account;
 use Espo\Modules\Crm\Entities\Opportunity;
 use tests\integration\Core\BaseTestCase;
+use tests\integration\testClasses\Entities\Account as AccountExtended;
+use tests\integration\testClasses\Entities\Opportunity as OpportunityExtended;
 
 class RelationsTest extends BaseTestCase
 {
     public function testGetOne(): void
     {
+        $metadata = $this->getMetadata();
+        $metadata->set('entityDefs', Opportunity::ENTITY_TYPE, [
+            'entityClassName' => OpportunityExtended::class,
+        ]);
+        $metadata->save();
+
+        $this->reCreateApplication();
+
         $em = $this->getEntityManager();
 
+        $opp = $em->getEntity(Opportunity::ENTITY_TYPE);
+        $this->assertInstanceOf(OpportunityExtended::class, $opp);
+        $this->assertNull($opp->getRelatedAccount());
+
         $account = $em->createEntity(Account::ENTITY_TYPE);
         $opp = $em->createEntity(Opportunity::ENTITY_TYPE, [
             'accountId' => $account->getId(),
         ]);
 
-        $account1 = $opp->get('account');
+        $this->assertInstanceOf(OpportunityExtended::class, $opp);
+
+        $account1 = $opp->getRelatedAccount();
 
         $this->assertInstanceOf(Account::class, $account1);
         $this->assertEquals($account->getId(), $account1->getId());
 
         $em->refreshEntity($opp);
 
-        $account2 = $opp->get('account');
+        $account2 = $opp->getRelatedAccount();
 
         $this->assertInstanceOf(Account::class, $account2);
         $this->assertNotSame($account1, $account2);
@@ -60,7 +76,7 @@ class RelationsTest extends BaseTestCase
 
         $em->saveEntity($opp);
 
-        $account3 = $opp->get('account');
+        $account3 = $opp->getRelatedAccount();
 
         $this->assertInstanceOf(Account::class, $account3);
         $this->assertNotSame($account1, $account3);
@@ -69,14 +85,28 @@ class RelationsTest extends BaseTestCase
 
     public function testGetMany(): void
     {
+        $metadata = $this->getMetadata();
+        $metadata->set('entityDefs', Account::ENTITY_TYPE, [
+            'entityClassName' => AccountExtended::class,
+        ]);
+        $metadata->save();
+
+        $this->reCreateApplication();
+
         $em = $this->getEntityManager();
 
+        $account = $em->getEntity(Account::ENTITY_TYPE);
+        $this->assertInstanceOf(AccountExtended::class, $account);
+        $this->assertInstanceOf(EntityCollection::class, $account->getRelatedOpportunities());
+
         $account = $em->createEntity(Account::ENTITY_TYPE);
+        $this->assertInstanceOf(AccountExtended::class, $account);
+
         $em->createEntity(Opportunity::ENTITY_TYPE, ['accountId' => $account->getId()]);
         $em->createEntity(Opportunity::ENTITY_TYPE, ['accountId' => $account->getId()]);
         $em->createEntity(Opportunity::ENTITY_TYPE);
 
-        $collection = $account->get('opportunities');
+        $collection = $account->getRelatedOpportunities();
 
         $this->assertInstanceOf(EntityCollection::class, $collection);
         $items = iterator_to_array($collection);
diff --git a/tests/integration/testClasses/Entities/Account.php b/tests/integration/testClasses/Entities/Account.php
new file mode 100644
index 0000000000..16b7561f4c
--- /dev/null
+++ b/tests/integration/testClasses/Entities/Account.php
@@ -0,0 +1,40 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM – Open Source CRM application.
+ * Copyright (C) 2014-2024 Yurii Kuznietsov, Taras Machyshyn, Oleksii Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU Affero General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU Affero General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace tests\integration\testClasses\Entities;
+
+use Espo\ORM\EntityCollection;
+
+class Account extends \Espo\Modules\Crm\Entities\Account
+{
+    public function getRelatedOpportunities(): EntityCollection
+    {
+        return $this->relations->getMany('opportunities');
+    }
+}
diff --git a/tests/integration/testClasses/Entities/Opportunity.php b/tests/integration/testClasses/Entities/Opportunity.php
new file mode 100644
index 0000000000..e38ad35c8e
--- /dev/null
+++ b/tests/integration/testClasses/Entities/Opportunity.php
@@ -0,0 +1,39 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM – Open Source CRM application.
+ * Copyright (C) 2014-2024 Yurii Kuznietsov, Taras Machyshyn, Oleksii Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU Affero General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU Affero General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace tests\integration\testClasses\Entities;
+
+class Opportunity extends \Espo\Modules\Crm\Entities\Opportunity
+{
+    public function getRelatedAccount(): ?\Espo\Modules\Crm\Entities\Account
+    {
+        /** @var ?\Espo\Modules\Crm\Entities\Account */
+        return $this->relations->getOne('account');
+    }
+}