diff --git a/validators/ExistValidator.php b/validators/ExistValidator.php
index be02f1a41..faea7b55d 100644
--- a/validators/ExistValidator.php
+++ b/validators/ExistValidator.php
@@ -162,7 +162,7 @@ private function checkTargetAttributeExistence($model, $attribute)
         }
 
         $params = $this->prepareConditions($targetAttribute, $model, $attribute);
-        $conditions = [$this->targetAttributeJunction == 'or' ? 'or' : 'and'];
+        $conditions = [$this->targetAttributeJunction === 'or' ? 'or' : 'and'];
 
         if (!$this->allowArray) {
             foreach ($params as $key => $value) {
@@ -264,17 +264,14 @@ protected function validateValue($value)
     private function valueExists($targetClass, $query, $value)
     {
         $db = $targetClass::getDb();
-        $exists = false;
 
         if ($this->forceMasterDb && method_exists($db, 'useMaster')) {
-            $exists = $db->useMaster(function () use ($query, $value) {
+            return $db->useMaster(function () use ($query, $value) {
                 return $this->queryValueExists($query, $value);
             });
-        } else {
-            $exists = $this->queryValueExists($query, $value);
         }
 
-        return $exists;
+        return $this->queryValueExists($query, $value);
     }
 
 
@@ -290,6 +287,7 @@ private function queryValueExists($query, $value)
         if (is_array($value)) {
             return $query->count("DISTINCT [[$this->targetAttribute]]") == count(array_unique($value));
         }
+
         return $query->exists();
     }
 
@@ -328,7 +326,7 @@ private function applyTableAlias($query, $conditions, $alias = null)
         foreach ($conditions as $columnName => $columnValue) {
             if (strpos($columnName, '(') === false) {
                 $prefixedColumn = "{$alias}.[[" . preg_replace(
-                    '/^' . preg_quote($alias) . '\.(.*)$/',
+                    '/^' . preg_quote($alias, '/') . '\.(.*)$/',
                     '$1',
                     $columnName) . ']]';
             } else {
diff --git a/validators/UniqueValidator.php b/validators/UniqueValidator.php
index 56bb0fe48..74edcfd66 100644
--- a/validators/UniqueValidator.php
+++ b/validators/UniqueValidator.php
@@ -189,8 +189,8 @@ private function modelExists($targetClass, $conditions, $model)
         /** @var ActiveRecordInterface|\yii\base\BaseObject $targetClass $query */
         $query = $this->prepareQuery($targetClass, $conditions);
 
-        if (!$model instanceof ActiveRecordInterface || $model->getIsNewRecord() || $model->className() !== $targetClass::className()) {
-            // if current $model isn't in the database yet then it's OK just to call exists()
+        if (!$model instanceof ActiveRecordInterface || $model->getIsNewRecord() || $model::className() !== $targetClass::className()) {
+            // if current $model isn't in the database yet, then it's OK just to call exists()
             // also there's no need to run check based on primary keys, when $targetClass is not the same as $model's class
             $exists = $query->exists();
         } else {
@@ -328,7 +328,7 @@ private function applyTableAlias($query, $conditions, $alias = null)
         $prefixedConditions = [];
         foreach ($conditions as $columnName => $columnValue) {
             if (strpos($columnName, '(') === false) {
-                $columnName = preg_replace('/^' . preg_quote($alias) . '\.(.*)$/', '$1', $columnName);
+                $columnName = preg_replace('/^' . preg_quote($alias, '/') . '\.(.*)$/', '$1', $columnName);
                 if (strncmp($columnName, '[[', 2) === 0) {
                     $prefixedColumn = "{$alias}.{$columnName}";
                 } else {