diff --git a/application/Espo/ORM/Locker/BaseLocker.php b/application/Espo/ORM/Locker/BaseLocker.php
index 8c482fe9e2..964dbe4e23 100644
--- a/application/Espo/ORM/Locker/BaseLocker.php
+++ b/application/Espo/ORM/Locker/BaseLocker.php
@@ -40,13 +40,13 @@ use RuntimeException;
 
 class BaseLocker implements Locker
 {
-    protected $pdo;
+    private $pdo;
 
-    protected $queryComposer;
+    private $queryComposer;
 
-    protected $transactionManager;
+    private $transactionManager;
 
-    protected $isLocked = false;
+    private $isLocked = false;
 
     public function __construct(PDO $pdo, QueryComposer $queryComposer, TransactionManager $transactionManager)
     {
diff --git a/application/Espo/ORM/Locker/MysqlLocker.php b/application/Espo/ORM/Locker/MysqlLocker.php
index 4f61672250..be0f9a0b2f 100644
--- a/application/Espo/ORM/Locker/MysqlLocker.php
+++ b/application/Espo/ORM/Locker/MysqlLocker.php
@@ -43,13 +43,13 @@ use RuntimeException;
  */
 class MysqlLocker implements Locker
 {
-    protected $pdo;
+    private $pdo;
 
-    protected $queryComposer;
+    private $queryComposer;
 
-    protected $transactionManager;
+    private $transactionManager;
 
-    protected $isLocked = false;
+    private $isLocked = false;
 
     public function __construct(PDO $pdo, QueryComposer $queryComposer, TransactionManager $transactionManager)
     {
diff --git a/application/Espo/ORM/QueryExecutor.php b/application/Espo/ORM/QueryExecutor.php
index dd18037b73..45380cd572 100644
--- a/application/Espo/ORM/QueryExecutor.php
+++ b/application/Espo/ORM/QueryExecutor.php
@@ -41,9 +41,9 @@ use PDOStatement;
  */
 class QueryExecutor
 {
-    protected $sqlExecutor;
+    private $sqlExecutor;
 
-    protected $queryComposer;
+    private $queryComposer;
 
     public function __construct(SqlExecutor $sqlExecutor, QueryComposer $queryComposer)
     {
diff --git a/application/Espo/ORM/Repository/RDBRelation.php b/application/Espo/ORM/Repository/RDBRelation.php
index 2bfeb7d16c..c7d35c3054 100644
--- a/application/Espo/ORM/Repository/RDBRelation.php
+++ b/application/Espo/ORM/Repository/RDBRelation.php
@@ -48,23 +48,23 @@ use RuntimeException;
  */
 class RDBRelation
 {
-    protected $entityManager;
+    private $entityManager;
 
-    protected $hookMediator;
+    private $hookMediator;
 
-    protected $entity;
+    private $entity;
 
-    protected $entityType;
+    private $entityType;
 
-    protected $foreignEntityType = null;
+    private $foreignEntityType = null;
 
-    protected $relationName;
+    private $relationName;
 
-    protected $relationType = null;
+    private $relationType = null;
 
-    protected $builder = null;
+    private $builder = null;
 
-    protected $noBuilder = false;
+    private $noBuilder = false;
 
     public function __construct(
         EntityManager $entityManager,
@@ -100,7 +100,7 @@ class RDBRelation
     /**
      * Create a select builder.
      */
-    protected function createSelectBuilder(?Select $query = null): Builder
+    private function createSelectBuilder(?Select $query = null): Builder
     {
         if ($this->noBuilder) {
             throw new RuntimeException("Can't use query builder for the '{$this->relationType}' relation type.");
@@ -125,12 +125,12 @@ class RDBRelation
         return $this->createSelectBuilder($query);
     }
 
-    protected function isBelongsToParentType(): bool
+    private function isBelongsToParentType(): bool
     {
         return $this->relationType === Entity::BELONGS_TO_PARENT;
     }
 
-    protected function getMapper(): RDBMapper
+    private function getMapper(): RDBMapper
     {
         return $this->entityManager->getMapper();
     }
@@ -340,7 +340,7 @@ class RDBRelation
         return $this->createSelectBuilder()->columnsWhere($clause);
     }
 
-    protected function processCheckForeignEntity(Entity $entity): void
+    private function processCheckForeignEntity(Entity $entity): void
     {
         if ($this->foreignEntityType && $this->foreignEntityType !== $entity->getEntityType()) {
             throw new RuntimeException("Entity type doesn't match an entity type of the relation.");
@@ -378,7 +378,7 @@ class RDBRelation
             ->findOne();
     }
 
-    protected function isRelatedBelongsToParent(Entity $entity): bool
+    private function isRelatedBelongsToParent(Entity $entity): bool
     {
         $fromEntity = $this->entity;
 
@@ -399,7 +399,7 @@ class RDBRelation
             $fromEntity->get($typeAttribute) === $entity->getEntityType();
     }
 
-    protected function isRelatedBelongsTo(Entity $entity): bool
+    private function isRelatedBelongsTo(Entity $entity): bool
     {
         $fromEntity = $this->entity;
 
@@ -554,32 +554,32 @@ class RDBRelation
         return $this->getMapper()->getRelationColumn($this->entity, $this->relationName, $entity->getId(), $column);
     }
 
-    protected function beforeRelate(Entity $entity, ?array $columnData, array $options): void
+    private function beforeRelate(Entity $entity, ?array $columnData, array $options): void
     {
         $this->hookMediator->beforeRelate($this->entity, $this->relationName, $entity, $columnData, $options);
     }
 
-    protected function afterRelate(Entity $entity, ?array $columnData, array $options): void
+    private function afterRelate(Entity $entity, ?array $columnData, array $options): void
     {
         $this->hookMediator->afterRelate($this->entity, $this->relationName, $entity, $columnData, $options);
     }
 
-    protected function beforeUnrelate(Entity $entity, array $options): void
+    private function beforeUnrelate(Entity $entity, array $options): void
     {
         $this->hookMediator->beforeUnrelate($this->entity, $this->relationName, $entity, $options);
     }
 
-    protected function afterUnrelate(Entity $entity, array $options): void
+    private function afterUnrelate(Entity $entity, array $options): void
     {
         $this->hookMediator->afterUnrelate($this->entity, $this->relationName, $entity, $options);
     }
 
-    protected function beforeMassRelate(Select $query, array $options): void
+    private function beforeMassRelate(Select $query, array $options): void
     {
         $this->hookMediator->beforeMassRelate($this->entity, $this->relationName, $query, $options);
     }
 
-    protected function afterMassRelate(Select $query, array $options): void
+    private function afterMassRelate(Select $query, array $options): void
     {
         $this->hookMediator->afterMassRelate($this->entity, $this->relationName, $query, $options);
     }
diff --git a/application/Espo/ORM/Repository/RDBRelationSelectBuilder.php b/application/Espo/ORM/Repository/RDBRelationSelectBuilder.php
index a8fc5be9f7..bd049b8e15 100644
--- a/application/Espo/ORM/Repository/RDBRelationSelectBuilder.php
+++ b/application/Espo/ORM/Repository/RDBRelationSelectBuilder.php
@@ -50,30 +50,26 @@ use InvalidArgumentException;
  */
 class RDBRelationSelectBuilder
 {
-    protected $entityManager;
+    private $entityManager;
 
-    protected $entity;
+    private $entity;
 
-    protected $entityType;
+    private $entityType;
 
-    protected $foreignEntityType;
+    private $foreignEntityType;
 
-    protected $relationName;
+    private $relationName;
 
-    protected $relationType = null;
+    private $relationType = null;
 
     /**
      * @var SelectBuilder
      */
-    protected $builder = null;
-
-    protected $additionalSelect = [];
-
-    protected $selectIsAdded = false;
+    private $builder = null;
 
     private $middleTableAlias = null;
 
-    protected $returnSthCollection = false;
+    private $returnSthCollection = false;
 
     public function __construct(
         EntityManager $entityManager,
diff --git a/application/Espo/ORM/Repository/RDBSelectBuilder.php b/application/Espo/ORM/Repository/RDBSelectBuilder.php
index 07215fd066..40bafa331a 100644
--- a/application/Espo/ORM/Repository/RDBSelectBuilder.php
+++ b/application/Espo/ORM/Repository/RDBSelectBuilder.php
@@ -49,15 +49,15 @@ use RuntimeException;
  */
 class RDBSelectBuilder
 {
-    protected $entityManager;
+    private $entityManager;
 
-    protected $builder;
+    private $builder;
 
-    protected $repository = null;
+    private $repository = null;
 
-    protected $entityType = null;
+    private $entityType = null;
 
-    protected $returnSthCollection = false;
+    private $returnSthCollection = false;
 
     public function __construct(EntityManager $entityManager, string $entityType, ?Select $query = null)
     {
diff --git a/application/Espo/ORM/Repository/RDBTransactionManager.php b/application/Espo/ORM/Repository/RDBTransactionManager.php
index 5b7d017ce4..cfb7e0b4ca 100644
--- a/application/Espo/ORM/Repository/RDBTransactionManager.php
+++ b/application/Espo/ORM/Repository/RDBTransactionManager.php
@@ -40,9 +40,9 @@ use RuntimeException;
  */
 class RDBTransactionManager
 {
-    protected $transactionManager;
+    private $transactionManager;
 
-    protected $level = 0;
+    private $level = 0;
 
     public function __construct(TransactionManager $transactionManager)
     {
diff --git a/application/Espo/ORM/SqlExecutor.php b/application/Espo/ORM/SqlExecutor.php
index 54777620fd..83a8496a5d 100644
--- a/application/Espo/ORM/SqlExecutor.php
+++ b/application/Espo/ORM/SqlExecutor.php
@@ -41,9 +41,9 @@ use RuntimeException;
  */
 class SqlExecutor
 {
-    protected $pdo;
+    private $pdo;
 
-    const MAX_ATTEMPT_COUNT = 4;
+    private const MAX_ATTEMPT_COUNT = 4;
 
     public function __construct(PDO $pdo)
     {
@@ -62,7 +62,7 @@ class SqlExecutor
         return $this->executeSqlWithDeadlockHandling($sql);
     }
 
-    protected function executeSqlWithDeadlockHandling(string $sql, ?int $counter = null): PDOStatement
+    private function executeSqlWithDeadlockHandling(string $sql, ?int $counter = null): PDOStatement
     {
         $counter = $counter ?? self::MAX_ATTEMPT_COUNT;
 
@@ -86,7 +86,7 @@ class SqlExecutor
         return $sth;
     }
 
-    protected function isExceptionIsDeadlock(Exception $e): bool
+    private function isExceptionIsDeadlock(Exception $e): bool
     {
         if (!$e instanceof PDOException) {
             return false;
diff --git a/application/Espo/ORM/TransactionManager.php b/application/Espo/ORM/TransactionManager.php
index 5e1d8e224a..17e5ab5c5c 100644
--- a/application/Espo/ORM/TransactionManager.php
+++ b/application/Espo/ORM/TransactionManager.php
@@ -40,11 +40,11 @@ use Closure;
 
 class TransactionManager
 {
-    protected $level = 0;
+    private $level = 0;
 
-    protected $pdo;
+    private $pdo;
 
-    protected $queryComposer;
+    private $queryComposer;
 
     public function __construct(PDO $pdo, QueryComposer $queryComposer)
     {
@@ -149,26 +149,26 @@ class TransactionManager
         $this->pdo->rollBack();
     }
 
-    protected function getCurrentSavepoint(): string
+    private function getCurrentSavepoint(): string
     {
         return 'POINT_' . (string) $this->level;
     }
 
-    protected function createSavepoint(): void
+    private function createSavepoint(): void
     {
         $sql = $this->queryComposer->composeCreateSavepoint($this->getCurrentSavepoint());
 
         $this->pdo->exec($sql);
     }
 
-    protected function releaseSavepoint(): void
+    private function releaseSavepoint(): void
     {
         $sql = $this->queryComposer->composeReleaseSavepoint($this->getCurrentSavepoint());
 
         $this->pdo->exec($sql);
     }
 
-    protected function rollbackToSavepoint(): void
+    private function rollbackToSavepoint(): void
     {
         $sql = $this->queryComposer->composeRollbackToSavepoint($this->getCurrentSavepoint());