diff --git a/db_qbe.php b/db_qbe.php
index 831e5cd0c3..f027cac32c 100644
--- a/db_qbe.php
+++ b/db_qbe.php
@@ -106,7 +106,7 @@ if ($message_to_display) {
 unset($message_to_display);
 
 // create new qbe search instance
-$db_qbe = new PMA_DBQbe($GLOBALS['db'], $savedSearchList, $savedSearch);
+$db_qbe = new PMA_DbQbe($GLOBALS['db'], $savedSearchList, $savedSearch);
 
 /**
  * Displays the Query by example form
diff --git a/index.php b/index.php
index 13b18eea5f..bb4e12742a 100644
--- a/index.php
+++ b/index.php
@@ -679,10 +679,10 @@ function PMA_printListItem($name, $listId = null, $url = null,
         if (null !== $target) {
             echo ' target="' . $target . '"';
         }
-        if (null != $a_id) {
+        if (null !== $a_id) {
             echo ' id="' . $a_id . '"';
         }
-        if (null != $a_class) {
+        if (null !== $a_class) {
             echo ' class="' . $a_class . '"';
         }
         echo '>';
diff --git a/tbl_operations.php b/tbl_operations.php
index d0e3a1dc02..efb1e954f5 100644
--- a/tbl_operations.php
+++ b/tbl_operations.php
@@ -410,7 +410,7 @@ if ($cfgRelation['relwork'] && ! $is_innodb) {
     $GLOBALS['dbi']->selectDb($GLOBALS['db']);
     $foreign = PMA_getForeigners($GLOBALS['db'], $GLOBALS['table'], '', 'internal');
 
-    if ($foreign) {
+    if (! empty($foreign)) {
         $response->addHTML(
             PMA_getHtmlForReferentialIntegrityCheck($foreign, $url_params)
         );