diff --git a/application/Espo/Core/Field/EmailAddress/EmailAddressGroupFactory.php b/application/Espo/Core/Field/EmailAddress/EmailAddressGroupFactory.php
index f821831048..6bdc6496a5 100644
--- a/application/Espo/Core/Field/EmailAddress/EmailAddressGroupFactory.php
+++ b/application/Espo/Core/Field/EmailAddress/EmailAddressGroupFactory.php
@@ -31,6 +31,7 @@ namespace Espo\Core\Field\EmailAddress;
 
 use Espo\Core\ORM\Type\FieldType;
 use Espo\Entities\EmailAddress as EmailAddressEntity;
+use Espo\ORM\Defs\Params\FieldParam;
 use Espo\Repositories\EmailAddress as Repository;
 
 use Espo\ORM\Entity;
@@ -63,7 +64,7 @@ class EmailAddressGroupFactory implements ValueFactory
 
     public function isCreatableFromEntity(Entity $entity, string $field): bool
     {
-        $type = $this->metadata->get(['entityDefs', $entity->getEntityType(), 'fields', $field, 'type']);
+        $type = $this->metadata->get(['entityDefs', $entity->getEntityType(), 'fields', $field, FieldParam::TYPE]);
 
         if ($type !== FieldType::EMAIL) {
             return false;
diff --git a/application/Espo/Core/Field/PhoneNumber/PhoneNumberGroupFactory.php b/application/Espo/Core/Field/PhoneNumber/PhoneNumberGroupFactory.php
index 4e01db015e..3a3b6d9dcc 100644
--- a/application/Espo/Core/Field/PhoneNumber/PhoneNumberGroupFactory.php
+++ b/application/Espo/Core/Field/PhoneNumber/PhoneNumberGroupFactory.php
@@ -31,6 +31,7 @@ namespace Espo\Core\Field\PhoneNumber;
 
 use Espo\Core\ORM\Type\FieldType;
 use Espo\Entities\PhoneNumber as PhoneNumberEntity;
+use Espo\ORM\Defs\Params\FieldParam;
 use Espo\Repositories\PhoneNumber as Repository;
 
 use Espo\ORM\Entity;
@@ -63,7 +64,7 @@ class PhoneNumberGroupFactory implements ValueFactory
 
     public function isCreatableFromEntity(Entity $entity, string $field): bool
     {
-        $type = $this->metadata->get(['entityDefs', $entity->getEntityType(), 'fields', $field, 'type']);
+        $type = $this->metadata->get(['entityDefs', $entity->getEntityType(), 'fields', $field, FieldParam::TYPE]);
 
         if ($type !== FieldType::PHONE) {
             return false;
diff --git a/application/Espo/Core/Record/Defaults/DefaultPopulator.php b/application/Espo/Core/Record/Defaults/DefaultPopulator.php
index a1aa84f3f4..0cd58a3482 100644
--- a/application/Espo/Core/Record/Defaults/DefaultPopulator.php
+++ b/application/Espo/Core/Record/Defaults/DefaultPopulator.php
@@ -38,6 +38,7 @@ use Espo\Core\ORM\Type\FieldType;
 use Espo\Core\Utils\Config;
 use Espo\Core\Utils\FieldUtil;
 use Espo\Entities\User;
+use Espo\ORM\Defs\Params\FieldParam;
 use Espo\ORM\Entity;
 use Espo\ORM\EntityManager;
 use RuntimeException;
@@ -85,7 +86,7 @@ class DefaultPopulator implements Populator
         }
 
         foreach ($this->fieldUtil->getEntityTypeFieldList($entityType) as $field) {
-            $type = $this->fieldUtil->getEntityTypeFieldParam($entityType, $field, 'type');
+            $type = $this->fieldUtil->getEntityTypeFieldParam($entityType, $field, FieldParam::TYPE);
 
             if (
                 $type === FieldType::CURRENCY &&
diff --git a/application/Espo/Core/Select/Order/ItemConverterFactory.php b/application/Espo/Core/Select/Order/ItemConverterFactory.php
index b823894201..7088df6f91 100644
--- a/application/Espo/Core/Select/Order/ItemConverterFactory.php
+++ b/application/Espo/Core/Select/Order/ItemConverterFactory.php
@@ -36,6 +36,7 @@ use Espo\Core\Utils\Metadata;
 use Espo\Core\Binding\BindingContainerBuilder;
 use Espo\Core\Binding\ContextualBinder;
 
+use Espo\ORM\Defs\Params\FieldParam;
 use RuntimeException;
 
 class ItemConverterFactory
@@ -84,7 +85,7 @@ class ItemConverterFactory
         }
 
         $type = $this->metadata->get([
-            'entityDefs', $entityType, 'fields', $field, 'type'
+            'entityDefs', $entityType, 'fields', $field, FieldParam::TYPE
         ]);
 
         if (!$type) {
diff --git a/application/Espo/Core/Select/Order/MetadataProvider.php b/application/Espo/Core/Select/Order/MetadataProvider.php
index 5f59de3627..07e113a563 100644
--- a/application/Espo/Core/Select/Order/MetadataProvider.php
+++ b/application/Espo/Core/Select/Order/MetadataProvider.php
@@ -30,6 +30,7 @@
 namespace Espo\Core\Select\Order;
 
 use Espo\Core\Utils\Metadata;
+use Espo\ORM\Defs\Params\FieldParam;
 use Espo\ORM\EntityManager;
 
 class MetadataProvider
@@ -40,7 +41,7 @@ class MetadataProvider
     public function getFieldType(string $entityType, string $field): ?string
     {
         return $this->metadata->get([
-            'entityDefs', $entityType, 'fields', $field, 'type'
+            'entityDefs', $entityType, 'fields', $field, FieldParam::TYPE
         ]) ?? null;
     }
 
diff --git a/application/Espo/Core/Select/Text/MetadataProvider.php b/application/Espo/Core/Select/Text/MetadataProvider.php
index fd663959e7..04b643d07e 100644
--- a/application/Espo/Core/Select/Text/MetadataProvider.php
+++ b/application/Espo/Core/Select/Text/MetadataProvider.php
@@ -32,6 +32,7 @@ namespace Espo\Core\Select\Text;
 use Espo\Core\Utils\Metadata;
 
 use Espo\ORM\Defs;
+use Espo\ORM\Defs\Params\FieldParam;
 
 class MetadataProvider
 {
@@ -69,7 +70,7 @@ class MetadataProvider
     public function isFullTextSearchSupportedForField(string $entityType, string $field): bool
     {
         $fieldType = $this->metadata->get([
-            'entityDefs', $entityType, 'fields', $field, 'type'
+            'entityDefs', $entityType, 'fields', $field, FieldParam::TYPE
         ]);
 
         return (bool) $this->metadata->get([
diff --git a/application/Espo/Core/Utils/Database/Orm/Converter.php b/application/Espo/Core/Utils/Database/Orm/Converter.php
index 5c5dcb83e2..1a20bdc280 100644
--- a/application/Espo/Core/Utils/Database/Orm/Converter.php
+++ b/application/Espo/Core/Utils/Database/Orm/Converter.php
@@ -42,6 +42,7 @@ use Espo\ORM\Defs\FieldDefs;
 use Espo\ORM\Defs\IndexDefs;
 use Espo\ORM\Defs\Params\AttributeParam;
 use Espo\ORM\Defs\Params\FieldParam;
+use Espo\ORM\Defs\Params\RelationParam;
 use Espo\ORM\Defs\RelationDefs;
 use Espo\ORM\Entity;
 use Espo\Core\Utils\Metadata;
@@ -73,7 +74,7 @@ class Converter
      * @var array<string, string>
      */
     private array $paramMap = [
-        'type' => 'type',
+        FieldParam::TYPE => AttributeParam::TYPE,
         FieldParam::DB_TYPE => AttributeParam::DB_TYPE,
         FieldParam::MAX_LENGTH => AttributeParam::LEN,
         'len' => AttributeParam::LEN, // @todo Revise.
@@ -255,7 +256,7 @@ class Converter
 
                 // Remove fields without type.
                 if (
-                    !isset($attributeParams['type']) &&
+                    !isset($attributeParams[AttributeParam::TYPE]) &&
                     (
                         !isset($attributeParams[AttributeParam::NOT_STORABLE]) ||
                         $attributeParams[AttributeParam::NOT_STORABLE] === false
@@ -266,7 +267,7 @@ class Converter
                     continue;
                 }
 
-                $attributeType = $attributeParams['type'] ?? null;
+                $attributeType = $attributeParams[AttributeParam::TYPE] ?? null;
 
                 switch ($attributeType) {
                     case Entity::ID:
@@ -306,7 +307,7 @@ class Converter
                         $constName = strtoupper(Util::toUnderScore($attributeType));
 
                         if (!defined('Espo\\ORM\\Type\\AttributeType::' . $constName)) {
-                            $attributeParams['type'] = $this->defaultAttributeType;
+                            $attributeParams[AttributeParam::TYPE] = $this->defaultAttributeType;
                         }
 
                         break;
@@ -325,7 +326,7 @@ class Converter
     {
         foreach ($ormMetadata as $entityType => &$entityParams) {
             foreach ($entityParams['attributes'] as $attribute => &$attributeParams) {
-                $attributeType = $attributeParams['type'] ?? null;
+                $attributeType = $attributeParams[AttributeParam::TYPE] ?? null;
 
                 switch ($attributeType) {
                     case Entity::FOREIGN:
@@ -364,7 +365,7 @@ class Converter
 
         $foreignParams = $data[$foreignEntityType]['attributes'][$foreign] ?? [];
 
-        return $foreignParams['type'] ?? null;
+        return $foreignParams[AttributeParam::TYPE] ?? null;
     }
 
     /**
@@ -376,30 +377,28 @@ class Converter
         $entityMetadata['fields'] ??= [];
 
         // List of unmerged fields with default field definitions in $output.
-        $unmergedFields = [
-            'name',
-        ];
+        $unmergedFields = [Field::NAME];
 
         $output = [
             Attribute::ID => [
-                'type' => Entity::ID,
+                AttributeParam::TYPE => Entity::ID,
             ],
             'name' => [
-                'type' => $entityMetadata['fields']['name']['type'] ?? Entity::VARCHAR,
+                AttributeParam::TYPE => $entityMetadata['fields'][Field::NAME][FieldParam::TYPE] ?? Entity::VARCHAR,
                 AttributeParam::NOT_STORABLE => true,
             ],
             Attribute::DELETED => [
-                'type' => Entity::BOOL,
+                AttributeParam::TYPE => Entity::BOOL,
                 'default' => false,
             ],
         ];
 
         if ($entityMetadata['noDeletedAttribute'] ?? false) {
-            unset($output['deleted']);
+            unset($output[Attribute::DELETED]);
         }
 
         foreach ($entityMetadata['fields'] as $attribute => $attributeParams) {
-            if (empty($attributeParams['type'])) {
+            if (empty($attributeParams[AttributeParam::TYPE])) {
                 continue;
             }
 
@@ -450,7 +449,7 @@ class Converter
         $entityMetadata = $ormMetadata[$entityType];
 
         foreach ($entityMetadata['attributes'] as $field => $itemParams) {
-            $type = $itemParams['type'] ?? null;
+            $type = $itemParams[AttributeParam::TYPE] ?? null;
 
             if (!$type) {
                 continue;
@@ -509,19 +508,19 @@ class Converter
         if ($scopeDefs['stream'] ?? false) {
             if (!isset($entityMetadata['fields'][Field::IS_FOLLOWED])) {
                 $ormMetadata[$entityType]['attributes'][Field::IS_FOLLOWED] = [
-                    'type' => Entity::BOOL,
+                    AttributeParam::TYPE => Entity::BOOL,
                     AttributeParam::NOT_STORABLE => true,
                     CoreAttributeParam::NOT_EXPORTABLE => true,
                 ];
 
                 $ormMetadata[$entityType]['attributes'][Field::FOLLOWERS . 'Ids'] = [
-                    'type' => Entity::JSON_ARRAY,
+                    AttributeParam::TYPE => Entity::JSON_ARRAY,
                     AttributeParam::NOT_STORABLE => true,
                     CoreAttributeParam::NOT_EXPORTABLE => true,
                 ];
 
                 $ormMetadata[$entityType]['attributes'][Field::FOLLOWERS . 'Names'] = [
-                    'type' => Entity::JSON_OBJECT,
+                    AttributeParam::TYPE => Entity::JSON_OBJECT,
                     AttributeParam::NOT_STORABLE => true,
                     CoreAttributeParam::NOT_EXPORTABLE => true,
                 ];
@@ -532,7 +531,7 @@ class Converter
         if ($scopeDefs['stars'] ?? false) {
             if (!isset($entityMetadata['fields'][Field::IS_STARRED])) {
                 $ormMetadata[$entityType]['attributes'][Field::IS_STARRED] = [
-                    'type' => Entity::BOOL,
+                    AttributeParam::TYPE => Entity::BOOL,
                     AttributeParam::NOT_STORABLE => true,
                     CoreAttributeParam::NOT_EXPORTABLE => true,
                     'readOnly' => true,
@@ -543,7 +542,7 @@ class Converter
         // @todo Refactor.
         if ($this->metadata->get(['entityDefs', $entityType, 'optimisticConcurrencyControl'])) {
             $ormMetadata[$entityType]['attributes']['versionNumber'] = [
-                'type' => Entity::INT,
+                AttributeParam::TYPE => Entity::INT,
                 AttributeParam::DB_TYPE => Types::BIGINT,
                 CoreAttributeParam::NOT_EXPORTABLE => true,
             ];
@@ -572,7 +571,7 @@ class Converter
             $fieldParams = Util::merge($fieldParams, $fieldTypeMetadata['fieldDefs']);
         }
 
-        if ($fieldParams['type'] == self::FIELD_TYPE_BASE && isset($fieldParams[FieldParam::DB_TYPE])) {
+        if ($fieldParams[FieldParam::TYPE] == self::FIELD_TYPE_BASE && isset($fieldParams[FieldParam::DB_TYPE])) {
             $fieldParams[FieldParam::NOT_STORABLE] = false;
         }
 
@@ -593,7 +592,7 @@ class Converter
             $fieldDefs[AttributeParam::NOT_STORABLE] = true;
         }
 
-        $type = $fieldDefs['type'] ?? null;
+        $type = $fieldDefs[FieldParam::TYPE] ?? null;
 
         if (
             $type &&
@@ -611,7 +610,7 @@ class Converter
      */
     private function prepareFieldParamsBeforeConvert(array &$fieldParams): void
     {
-        $type = $fieldParams['type'] ?? null;
+        $type = $fieldParams[FieldParam::TYPE] ?? null;
 
         if ($type === FieldType::ENUM) {
             if (($fieldParams['default'] ?? null) === '') {
@@ -681,8 +680,8 @@ class Converter
             }
         }
 
-        if (isset($attributeParams['type'])) {
-            $values['fieldType'] = $attributeParams['type'];
+        if (isset($attributeParams[AttributeParam::TYPE])) {
+            $values['fieldType'] = $attributeParams[AttributeParam::TYPE];
         }
 
         return $values;
@@ -705,11 +704,11 @@ class Converter
         foreach ($fieldList as $field) {
             $defs = $this->metadata->get(['entityDefs', $entityType, 'fields', $field], []);
 
-            if (empty($defs['type'])) {
+            if (empty($defs[FieldParam::TYPE])) {
                 continue;
             }
 
-            $fieldType = $defs['type'];
+            $fieldType = $defs[FieldParam::TYPE];
 
             if (!empty($defs[FieldParam::NOT_STORABLE])) {
                 continue;
@@ -779,7 +778,7 @@ class Converter
 
         if (isset($defs['relations'])) {
             foreach ($defs['relations'] as &$relationData) {
-                $type = $relationData['type'] ?? null;
+                $type = $relationData[RelationParam::TYPE] ?? null;
 
                 if ($type !== Entity::MANY_MANY) {
                     continue;
@@ -892,12 +891,12 @@ class Converter
                 'skipRebuild' => true,
                 'attributes' => [
                     Attribute::ID => [
-                        'type' => Entity::ID,
+                        AttributeParam::TYPE => Entity::ID,
                         'autoincrement' => true,
                         AttributeParam::DB_TYPE => Types::BIGINT, // ignored because of `skipRebuild`
                     ],
                     Attribute::DELETED => [
-                        'type' => Entity::BOOL,
+                        AttributeParam::TYPE => Entity::BOOL,
                     ],
                 ],
             ];
@@ -914,17 +913,17 @@ class Converter
 
             foreach ($midKeys as $key) {
                 $itemDefs['attributes'][$key] = [
-                    'type' => Entity::FOREIGN_ID,
+                    AttributeParam::TYPE => Entity::FOREIGN_ID,
                 ];
             }
 
             foreach ($relationDefs->getParam('additionalColumns') ?? [] as $columnName => $columnItem) {
-                $columnItem['type'] ??= Entity::VARCHAR;
+                $columnItem[AttributeParam::TYPE] ??= Entity::VARCHAR;
 
                 $attributeDefs = AttributeDefs::fromRaw($columnItem, $columnName);
 
                 $columnDefs = [
-                    'type' => $attributeDefs->getType(),
+                    AttributeParam::TYPE => $attributeDefs->getType(),
                 ];
 
                 if ($attributeDefs->getLength()) {
diff --git a/application/Espo/Core/Utils/Database/Orm/Defs/AttributeDefs.php b/application/Espo/Core/Utils/Database/Orm/Defs/AttributeDefs.php
index d1e2a5d319..1e8c3f2c36 100644
--- a/application/Espo/Core/Utils/Database/Orm/Defs/AttributeDefs.php
+++ b/application/Espo/Core/Utils/Database/Orm/Defs/AttributeDefs.php
@@ -64,7 +64,7 @@ class AttributeDefs
     public function getType(): ?string
     {
         /** @var ?AttributeType::* $value */
-        $value = $this->getParam('type');
+        $value = $this->getParam(AttributeParam::TYPE);
 
         return $value;
     }
@@ -76,7 +76,7 @@ class AttributeDefs
      */
     public function withType(string $type): self
     {
-        return $this->withParam('type', $type);
+        return $this->withParam(AttributeParam::TYPE, $type);
     }
 
     /**
diff --git a/application/Espo/Core/Utils/FieldUtil.php b/application/Espo/Core/Utils/FieldUtil.php
index 0a68aef552..90594de777 100644
--- a/application/Espo/Core/Utils/FieldUtil.php
+++ b/application/Espo/Core/Utils/FieldUtil.php
@@ -29,6 +29,8 @@
 
 namespace Espo\Core\Utils;
 
+use Espo\ORM\Defs\Params\FieldParam;
+
 class FieldUtil
 {
     /** @var array<string, array<string, string[]>> */
@@ -113,7 +115,7 @@ class FieldUtil
             return [];
         }
 
-        $type = $this->metadata->get(['entityDefs', $entityType, 'fields', $name, 'type']);
+        $type = $this->metadata->get(['entityDefs', $entityType, 'fields', $name, FieldParam::TYPE]);
 
         if (!$type) {
             return [];
diff --git a/application/Espo/ORM/BaseEntity.php b/application/Espo/ORM/BaseEntity.php
index 250a7fbac9..f5cdb043d8 100644
--- a/application/Espo/ORM/BaseEntity.php
+++ b/application/Espo/ORM/BaseEntity.php
@@ -31,6 +31,8 @@ namespace Espo\ORM;
 
 use Espo\ORM\DataLoader\EmptyLoader;
 use Espo\ORM\DataLoader\Loader;
+use Espo\ORM\Defs\Params\AttributeParam;
+use Espo\ORM\Defs\Params\RelationParam;
 use Espo\ORM\Name\Attribute;
 use Espo\ORM\Relation\EmptyRelations;
 use Espo\ORM\Relation\Relations;
@@ -720,7 +722,7 @@ class BaseEntity implements Entity
             return null;
         }
 
-        return $this->attributesDefs[$attribute]['type'] ?? null;
+        return $this->attributesDefs[$attribute][AttributeParam::TYPE] ?? null;
     }
 
     /**
@@ -732,7 +734,7 @@ class BaseEntity implements Entity
             return null;
         }
 
-        return $this->relationsDefs[$relation]['type'] ?? null;
+        return $this->relationsDefs[$relation][RelationParam::TYPE] ?? null;
     }
 
     /**
diff --git a/application/Espo/ORM/Defs/AttributeDefs.php b/application/Espo/ORM/Defs/AttributeDefs.php
index 317bc8d8b6..bde07bde65 100644
--- a/application/Espo/ORM/Defs/AttributeDefs.php
+++ b/application/Espo/ORM/Defs/AttributeDefs.php
@@ -68,7 +68,7 @@ class AttributeDefs
      */
     public function getType(): string
     {
-        return $this->data['type'];
+        return $this->data[AttributeParam::TYPE];
     }
 
     /**
diff --git a/application/Espo/ORM/Defs/FieldDefs.php b/application/Espo/ORM/Defs/FieldDefs.php
index 238eb26060..4375984b25 100644
--- a/application/Espo/ORM/Defs/FieldDefs.php
+++ b/application/Espo/ORM/Defs/FieldDefs.php
@@ -69,7 +69,7 @@ class FieldDefs
      */
     public function getType(): string
     {
-        $type = $this->data['type'] ?? null;
+        $type = $this->data[FieldParam::TYPE] ?? null;
 
         if ($type === null) {
             throw new RuntimeException("Field '$this->name' has no type.");
diff --git a/application/Espo/ORM/Defs/Params/AttributeParam.php b/application/Espo/ORM/Defs/Params/AttributeParam.php
index 9790ef89da..16f487b1b3 100644
--- a/application/Espo/ORM/Defs/Params/AttributeParam.php
+++ b/application/Espo/ORM/Defs/Params/AttributeParam.php
@@ -29,8 +29,16 @@
 
 namespace Espo\ORM\Defs\Params;
 
+/**
+ * An attribute parameter.
+ */
 class AttributeParam
 {
+    /**
+     * A type.
+     */
+    public const TYPE = 'type';
+
     /**
      * Not stored in database.
      */
diff --git a/application/Espo/ORM/Defs/Params/FieldParam.php b/application/Espo/ORM/Defs/Params/FieldParam.php
index 83fcc296a0..b7a1ef59d3 100644
--- a/application/Espo/ORM/Defs/Params/FieldParam.php
+++ b/application/Espo/ORM/Defs/Params/FieldParam.php
@@ -29,8 +29,16 @@
 
 namespace Espo\ORM\Defs\Params;
 
+/**
+ * A field parameter.
+ */
 class FieldParam
 {
+    /**
+     * A type.
+     */
+    public const TYPE = 'type';
+
     /**
      * Not stored in database.
      */
diff --git a/application/Espo/ORM/Defs/Params/RelationParam.php b/application/Espo/ORM/Defs/Params/RelationParam.php
new file mode 100644
index 0000000000..70277e4b89
--- /dev/null
+++ b/application/Espo/ORM/Defs/Params/RelationParam.php
@@ -0,0 +1,41 @@
+<?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 Espo\ORM\Defs\Params;
+
+/**
+ * A relation parameter.
+ */
+class RelationParam
+{
+    /**
+     * A type.
+     */
+    public const TYPE = 'type';
+}
diff --git a/application/Espo/ORM/Defs/RelationDefs.php b/application/Espo/ORM/Defs/RelationDefs.php
index 7abef739cc..5bda47db7a 100644
--- a/application/Espo/ORM/Defs/RelationDefs.php
+++ b/application/Espo/ORM/Defs/RelationDefs.php
@@ -29,6 +29,7 @@
 
 namespace Espo\ORM\Defs;
 
+use Espo\ORM\Defs\Params\RelationParam;
 use Espo\ORM\Entity;
 
 use RuntimeException;
@@ -70,7 +71,7 @@ class RelationDefs
      */
     public function getType(): string
     {
-        $type = $this->data['type'] ?? null;
+        $type = $this->data[RelationParam::TYPE] ?? null;
 
         if ($type === null) {
             throw new RuntimeException("Relation '{$this->name}' has no type.");
diff --git a/application/Espo/ORM/Mapper/BaseMapper.php b/application/Espo/ORM/Mapper/BaseMapper.php
index 5514f9ef2f..8b70d3f80d 100644
--- a/application/Espo/ORM/Mapper/BaseMapper.php
+++ b/application/Espo/ORM/Mapper/BaseMapper.php
@@ -30,6 +30,7 @@
 namespace Espo\ORM\Mapper;
 
 use Espo\ORM\Defs\Params\AttributeParam;
+use Espo\ORM\Defs\Params\RelationParam;
 use Espo\ORM\Entity;
 use Espo\ORM\BaseEntity;
 use Espo\ORM\Collection;
@@ -678,7 +679,7 @@ class BaseMapper implements RDBMapper
             return null;
         }
 
-        $columnType = $additionalColumns[$column]['type'] ?? Entity::VARCHAR;
+        $columnType = $additionalColumns[$column][AttributeParam::TYPE] ?? Entity::VARCHAR;
 
         $where = [
             $nearKey => $entity->getId(),
@@ -854,7 +855,7 @@ class BaseMapper implements RDBMapper
 
                 if (
                     $foreignRelationName &&
-                    $this->getRelationParam($relEntity, $foreignRelationName, 'type') === Entity::HAS_ONE
+                    $this->getRelationParam($relEntity, $foreignRelationName, RelationParam::TYPE) === Entity::HAS_ONE
                 ) {
                     $where = [
                         self::ATTR_ID . '!=' => $entity->getId(),