diff --git a/src/Config/Form.php b/src/Config/Form.php
index f306d4fd27..f22fd3db29 100644
--- a/src/Config/Form.php
+++ b/src/Config/Form.php
@@ -84,9 +84,9 @@ class Form
      *
      * @param string $optionName path or field name
      *
-     * @return string|null one of: boolean, integer, double, string, select, array
+     * @return string one of: boolean, integer, double, string, select, array
      */
-    public function getOptionType(string $optionName): string|null
+    public function getOptionType(string $optionName): string
     {
         $key = ltrim(
             mb_substr(
@@ -96,7 +96,7 @@ class Form
             '/',
         );
 
-        return $this->fieldsTypes[$key] ?? null;
+        return $this->fieldsTypes[$key] ?? '';
     }
 
     /**
diff --git a/src/Config/FormDisplay.php b/src/Config/FormDisplay.php
index feafec89ff..326a695857 100644
--- a/src/Config/FormDisplay.php
+++ b/src/Config/FormDisplay.php
@@ -566,7 +566,7 @@ class FormDisplay
             foreach ($form->fields as $field => $systemPath) {
                 $workPath = array_search($systemPath, $this->systemPaths);
                 $key = $this->translatedPaths[$workPath];
-                $type = (string) $form->getOptionType($field);
+                $type = $form->getOptionType($field);
 
                 // skip groups
                 if ($type === 'group') {
diff --git a/src/ConfigStorage/Relation.php b/src/ConfigStorage/Relation.php
index 1b4898e535..c7200ac646 100644
--- a/src/ConfigStorage/Relation.php
+++ b/src/ConfigStorage/Relation.php
@@ -1235,10 +1235,10 @@ class Relation
     /**
      * Create a PDF page
      *
-     * @param string|null $newpage name of the new PDF page
-     * @param string      $db      database name
+     * @param string $newpage name of the new PDF page
+     * @param string $db      database name
      */
-    public function createPage(string|null $newpage, PdfFeature $pdfFeature, string $db): int
+    public function createPage(string $newpage, PdfFeature $pdfFeature, string $db): int
     {
         $insQuery = 'INSERT INTO '
             . Util::backquote($pdfFeature->database) . '.'
@@ -1247,7 +1247,7 @@ class Relation
             . ' VALUES ('
             . $this->dbi->quoteString($db, ConnectionType::ControlUser) . ', '
             . $this->dbi->quoteString(
-                $newpage !== null && $newpage !== '' ? $newpage : __('no description'),
+                $newpage !== '' ? $newpage : __('no description'),
                 ConnectionType::ControlUser,
             ) . ')';
         $this->dbi->tryQueryAsControlUser($insQuery);
diff --git a/src/Controllers/Database/CentralColumnsController.php b/src/Controllers/Database/CentralColumnsController.php
index a0b5325238..98d59a9146 100644
--- a/src/Controllers/Database/CentralColumnsController.php
+++ b/src/Controllers/Database/CentralColumnsController.php
@@ -42,7 +42,7 @@ final class CentralColumnsController implements InvocableController
                 $request->getParsedBodyParamAsString('orig_col_name'),
                 $request->getParsedBodyParamAsString('col_default'),
                 $request->getParsedBodyParamAsString('col_default_sel'),
-                $request->getParsedBodyParamAsStringOrNull('col_extra'),
+                $request->getParsedBodyParamAsString('col_extra', ''),
                 $request->getParsedBodyParamAsStringOrNull('col_isNull'),
                 $request->getParsedBodyParamAsString('col_length'),
                 $request->getParsedBodyParamAsString('col_attribute'),
@@ -60,7 +60,7 @@ final class CentralColumnsController implements InvocableController
                 $request->getParsedBodyParamAsString('col_name'),
                 $request->getParsedBodyParamAsString('col_default'),
                 $request->getParsedBodyParamAsString('col_default_sel'),
-                $request->getParsedBodyParamAsStringOrNull('col_extra'),
+                $request->getParsedBodyParamAsString('col_extra', ''),
                 $request->getParsedBodyParamAsStringOrNull('col_isNull'),
                 $request->getParsedBodyParamAsString('col_length'),
                 $request->getParsedBodyParamAsString('col_attribute'),
@@ -176,7 +176,7 @@ final class CentralColumnsController implements InvocableController
         string $origColName,
         string $colDefault,
         string $colDefaultSel,
-        string|null $colExtra,
+        string $colExtra,
         string|null $colIsNull,
         string $colLength,
         string $colAttribute,
@@ -198,7 +198,7 @@ final class CentralColumnsController implements InvocableController
             $colLength,
             $colIsNull !== null,
             $collation,
-            $colExtra ?? '',
+            $colExtra,
             $columnDefault,
         );
     }
@@ -207,7 +207,7 @@ final class CentralColumnsController implements InvocableController
         string $colName,
         string $colDefault,
         string $colDefaultSel,
-        string|null $colExtra,
+        string $colExtra,
         string|null $colIsNull,
         string $colLength,
         string $colAttribute,
@@ -224,7 +224,7 @@ final class CentralColumnsController implements InvocableController
             $colLength,
             $colIsNull !== null,
             $collation,
-            $colExtra ?? '',
+            $colExtra,
             $colDefault === 'NONE' && $colDefaultSel !== 'USER_DEFINED' ? '' : $colDefault,
         );
     }
diff --git a/tests/unit/Config/FormTest.php b/tests/unit/Config/FormTest.php
index 593ea98bbc..586d9a24e4 100644
--- a/tests/unit/Config/FormTest.php
+++ b/tests/unit/Config/FormTest.php
@@ -68,7 +68,8 @@ class FormTest extends AbstractTestCase
             ['7' => 'Seven'],
         );
 
-        self::assertNull(
+        self::assertSame(
+            '',
             $this->object->getOptionType('123/4/5/6'),
         );