diff --git a/library/Icingadb/Setup/ApiTransportPage.php b/library/Icingadb/Setup/ApiTransportPage.php
index e727e997..d46c7fd7 100644
--- a/library/Icingadb/Setup/ApiTransportPage.php
+++ b/library/Icingadb/Setup/ApiTransportPage.php
@@ -71,7 +71,7 @@ class ApiTransportPage extends Form
             return false;
         }
 
-        if (! isset($formData['skip_validation']) || !$formData['skip_validation']) {
+        if (! isset($formData['skip_validation']) || ! $formData['skip_validation']) {
             if (! $this->validateConfiguration()) {
                 $this->addSkipValidationCheckbox();
                 return false;
diff --git a/library/Icingadb/Setup/DbResourcePage.php b/library/Icingadb/Setup/DbResourcePage.php
index 3c3cbf8d..bca0b776 100644
--- a/library/Icingadb/Setup/DbResourcePage.php
+++ b/library/Icingadb/Setup/DbResourcePage.php
@@ -88,7 +88,7 @@ class DbResourcePage extends Form
             return false;
         }
 
-        if (! isset($formData['skip_validation']) || !$formData['skip_validation']) {
+        if (! isset($formData['skip_validation']) || ! $formData['skip_validation']) {
             if (! $this->validateConfiguration()) {
                 $this->addSkipValidationCheckbox();
                 return false;
diff --git a/library/Icingadb/Web/Controller.php b/library/Icingadb/Web/Controller.php
index ae812047..00119e7b 100644
--- a/library/Icingadb/Web/Controller.php
+++ b/library/Icingadb/Web/Controller.php
@@ -351,7 +351,7 @@ class Controller extends CompatController
                     }
                 }
 
-                if (!empty($unused)) {
+                if (! empty($unused)) {
                     $sql .= ' /* Unused values: "' . join('", "', $unused) . '" */';
                 }