diff --git a/db_create.php b/db_create.php
index 54440b62dd..76e9cb5737 100644
--- a/db_create.php
+++ b/db_create.php
@@ -17,6 +17,10 @@ if (! PMA_DRIZZLE) {
 }
 require 'libraries/build_html_for_db.lib.php';
 
+if (! isset($_POST['new_db'])) {
+    PMA_Util::checkParameters(array('new_db'));
+}
+
 /**
  * Defines the url to return to in case of error in a sql statement
  */
diff --git a/export.php b/export.php
index b7942a34ac..b781eaa18d 100644
--- a/export.php
+++ b/export.php
@@ -163,11 +163,12 @@ if (!defined('TESTSUITE')) {
     }
 
     $table = $GLOBALS['table'];
-    // sanitize this parameter which will be used below in a file inclusion
-    $what = PMA_securePath($_POST['what']);
 
     PMA_Util::checkParameters(array('what', 'export_type'));
 
+    // sanitize this parameter which will be used below in a file inclusion
+    $what = PMA_securePath($_POST['what']);
+
     // export class instance, not array of properties, as before
     /* @var $export_plugin ExportPlugin */
     $export_plugin = PMA_getPlugin(
diff --git a/gis_data_editor.php b/gis_data_editor.php
index ac876da4d9..be13aeeb0e 100644
--- a/gis_data_editor.php
+++ b/gis_data_editor.php
@@ -23,6 +23,10 @@ require_once 'libraries/common.inc.php';
 require_once 'libraries/gis/GIS_Factory.class.php';
 require_once 'libraries/gis/GIS_Visualization.class.php';
 
+if (! isset($_REQUEST['field'])) {
+    PMA_Util::checkParameters(array('field'));
+}
+
 // Get data if any posted
 $gis_data = array();
 if (PMA_isValid($_REQUEST['gis_data'], 'array')) {
@@ -185,6 +189,9 @@ if ($geom_type == 'GEOMETRYCOLLECTION') {
 }
 
 for ($a = 0; $a < $geom_count; $a++) {
+    if (! isset($gis_data[$a])) {
+        continue;
+    }
 
     if ($geom_type == 'GEOMETRYCOLLECTION') {
         echo '<br/><br/>';
diff --git a/libraries/sql.lib.php b/libraries/sql.lib.php
index 352800985b..20b0fe6fd7 100644
--- a/libraries/sql.lib.php
+++ b/libraries/sql.lib.php
@@ -2029,7 +2029,8 @@ function PMA_executeQueryAndGetQueryResponse($analyzed_sql_results,
     // (the parser never sets the 'union' key to 0).
     // Handling is also not required if we came from the "Sort by key"
     // drop-down.
-    if (PMA_isRememberSortingOrder($analyzed_sql_results)
+    if (! empty($analyzed_sql_results)
+        && PMA_isRememberSortingOrder($analyzed_sql_results)
         && empty($analyzed_sql_results['union'])
         && ! isset($_REQUEST['sort_by_key'])
     ) {
diff --git a/schema_export.php b/schema_export.php
index ec1c4e0b54..b28ae6758f 100644
--- a/schema_export.php
+++ b/schema_export.php
@@ -22,6 +22,10 @@ require_once 'libraries/Index.class.php';
 require_once 'libraries/pmd_common.php';
 require_once 'libraries/plugin_interface.lib.php';
 
+if (! isset($_REQUEST['export_type'])) {
+    PMA_Util::checkParameters(array('export_type'));
+}
+
 /**
  * Include the appropriate Schema Class depending on $export_type
  * default is PDF