diff --git a/libraries/classes/Plugins/Schema/Dia/DiaRelationSchema.php b/libraries/classes/Plugins/Schema/Dia/DiaRelationSchema.php
index dc6a29ad2c..3c8fa53cb3 100644
--- a/libraries/classes/Plugins/Schema/Dia/DiaRelationSchema.php
+++ b/libraries/classes/Plugins/Schema/Dia/DiaRelationSchema.php
@@ -52,8 +52,8 @@ class DiaRelationSchema extends ExportRelationSchema
 
         $this->setShowColor(isset($_REQUEST['dia_show_color']));
         $this->setShowKeys(isset($_REQUEST['dia_show_keys']));
-        $this->setOrientation($_REQUEST['dia_orientation']);
-        $this->setPaper($_REQUEST['dia_paper']);
+        $this->setOrientation((string) $_REQUEST['dia_orientation']);
+        $this->setPaper((string) $_REQUEST['dia_paper']);
 
         $this->diagram->startDiaDoc(
             $this->paper,
diff --git a/libraries/classes/Plugins/Schema/Eps/EpsRelationSchema.php b/libraries/classes/Plugins/Schema/Eps/EpsRelationSchema.php
index e16beb5a86..0c424a8266 100644
--- a/libraries/classes/Plugins/Schema/Eps/EpsRelationSchema.php
+++ b/libraries/classes/Plugins/Schema/Eps/EpsRelationSchema.php
@@ -53,7 +53,7 @@ class EpsRelationSchema extends ExportRelationSchema
         $this->setShowKeys(isset($_REQUEST['eps_show_keys']));
         $this->setTableDimension(isset($_REQUEST['eps_show_table_dimension']));
         $this->setAllTablesSameWidth(isset($_REQUEST['eps_all_tables_same_width']));
-        $this->setOrientation($_REQUEST['eps_orientation']);
+        $this->setOrientation((string) $_REQUEST['eps_orientation']);
 
         $this->diagram->setTitle(
             sprintf(
diff --git a/libraries/classes/Plugins/Schema/ExportRelationSchema.php b/libraries/classes/Plugins/Schema/ExportRelationSchema.php
index 2a2c29fcb2..1fb38f2298 100644
--- a/libraries/classes/Plugins/Schema/ExportRelationSchema.php
+++ b/libraries/classes/Plugins/Schema/ExportRelationSchema.php
@@ -11,7 +11,6 @@ use PhpMyAdmin\Relation;
 use PhpMyAdmin\Url;
 use PhpMyAdmin\Util;
 use function htmlspecialchars;
-use function intval;
 use function rawurldecode;
 
 /**
@@ -43,7 +42,7 @@ class ExportRelationSchema
     {
         $this->db = $db;
         $this->diagram = $diagram;
-        $this->setPageNumber($_REQUEST['page_number']);
+        $this->setPageNumber((int) $_REQUEST['page_number']);
         $this->setOffline(isset($_REQUEST['offline_export']));
         $this->relation = new Relation($GLOBALS['dbi']);
     }
@@ -55,9 +54,9 @@ class ExportRelationSchema
      *
      * @return void
      */
-    public function setPageNumber($value)
+    public function setPageNumber(int $value): void
     {
-        $this->pageNumber = intval($value);
+        $this->pageNumber = $value;
     }
 
     /**
@@ -77,7 +76,7 @@ class ExportRelationSchema
      *
      * @return void
      */
-    public function setShowColor($value)
+    public function setShowColor(bool $value): void
     {
         $this->showColor = $value;
     }
@@ -99,7 +98,7 @@ class ExportRelationSchema
      *
      * @return void
      */
-    public function setTableDimension($value)
+    public function setTableDimension(bool $value): void
     {
         $this->tableDimension = $value;
     }
@@ -121,7 +120,7 @@ class ExportRelationSchema
      *
      * @return void
      */
-    public function setAllTablesSameWidth($value)
+    public function setAllTablesSameWidth(bool $value): void
     {
         $this->sameWide = $value;
     }
@@ -145,7 +144,7 @@ class ExportRelationSchema
      *
      * @access public
      */
-    public function setShowKeys($value)
+    public function setShowKeys(bool $value): void
     {
         $this->showKeys = $value;
     }
@@ -169,7 +168,7 @@ class ExportRelationSchema
      *
      * @access public
      */
-    public function setOrientation($value)
+    public function setOrientation(string $value): void
     {
         $this->orientation = $value == 'P' ? 'P' : 'L';
     }
@@ -193,7 +192,7 @@ class ExportRelationSchema
      *
      * @access public
      */
-    public function setPaper($value)
+    public function setPaper(string $value): void
     {
         $this->paper = $value;
     }
@@ -217,7 +216,7 @@ class ExportRelationSchema
      *
      * @access public
      */
-    public function setOffline($value)
+    public function setOffline(bool $value): void
     {
         $this->offline = $value;
     }
@@ -237,9 +236,9 @@ class ExportRelationSchema
     /**
      * Get the table names from the request
      *
-     * @return array an array of table names
+     * @return string[] an array of table names
      */
-    protected function getTablesFromRequest()
+    protected function getTablesFromRequest(): array
     {
         $tables = [];
         if (isset($_POST['t_tbl'])) {
diff --git a/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php b/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php
index ddfe9bf400..3574d7cbea 100644
--- a/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php
+++ b/libraries/classes/Plugins/Schema/Pdf/PdfRelationSchema.php
@@ -96,8 +96,8 @@ class PdfRelationSchema extends ExportRelationSchema
         $this->setAllTablesSameWidth(isset($_REQUEST['pdf_all_tables_same_width']));
         $this->setWithDataDictionary(isset($_REQUEST['pdf_with_doc']));
         $this->setTableOrder($_REQUEST['pdf_table_order']);
-        $this->setOrientation($_REQUEST['pdf_orientation']);
-        $this->setPaper($_REQUEST['pdf_paper']);
+        $this->setOrientation((string) $_REQUEST['pdf_orientation']);
+        $this->setPaper((string) $_REQUEST['pdf_paper']);
 
         // Initializes a new document
         parent::__construct(
diff --git a/libraries/classes/Plugins/Schema/Svg/TableStatsSvg.php b/libraries/classes/Plugins/Schema/Svg/TableStatsSvg.php
index 952c09afb9..a3923c6225 100644
--- a/libraries/classes/Plugins/Schema/Svg/TableStatsSvg.php
+++ b/libraries/classes/Plugins/Schema/Svg/TableStatsSvg.php
@@ -83,7 +83,7 @@ class TableStatsSvg extends TableStats
      *
      * @return void
      */
-    protected function showMissingTableError()
+    protected function showMissingTableError(): void
     {
         ExportRelationSchema::dieSchema(
             $this->pageNumber,
@@ -104,7 +104,7 @@ class TableStatsSvg extends TableStats
      *
      * @access private
      */
-    private function _setWidthTable($font, $fontSize)
+    private function _setWidthTable($font, $fontSize): void
     {
         foreach ($this->fields as $field) {
             $this->width = max(
@@ -132,7 +132,7 @@ class TableStatsSvg extends TableStats
      *
      * @return void
      */
-    private function _setHeightTable($fontSize)
+    private function _setHeightTable($fontSize): void
     {
         $this->heightCell = $fontSize + 4;
         $this->height = (count($this->fields) + 1) * $this->heightCell;
@@ -149,7 +149,7 @@ class TableStatsSvg extends TableStats
      *
      * @access public
      */
-    public function tableDraw($showColor)
+    public function tableDraw($showColor): void
     {
         $this->diagram->printElement(
             'rect',