diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 5d53a9ac..e00f4195 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -36,6 +36,12 @@ parameters:
 			count: 1
 			path: src/DatabaseDriver.php
 
+		-
+			message: '#^Call to function is_string\(\) with string will always evaluate to true\.$#'
+			identifier: function.alreadyNarrowedType
+			count: 1
+			path: src/DatabaseDriver.php
+
 		-
 			message: '#^If condition is always true\.$#'
 			identifier: if.alwaysTrue
@@ -72,6 +78,12 @@ parameters:
 			count: 1
 			path: src/DatabaseDriver.php
 
+		-
+			message: '#^Result of \|\| is always false\.$#'
+			identifier: booleanOr.alwaysFalse
+			count: 1
+			path: src/DatabaseDriver.php
+
 		-
 			message: '#^Strict comparison using \=\=\= between ''resource''\|''resource \(closed\)'' and ''object'' will always evaluate to false\.$#'
 			identifier: identical.alwaysFalse
@@ -84,6 +96,12 @@ parameters:
 			count: 1
 			path: src/DatabaseDriver.php
 
+		-
+			message: '#^Strict comparison using \=\=\= between string and null will always evaluate to false\.$#'
+			identifier: identical.alwaysFalse
+			count: 1
+			path: src/DatabaseDriver.php
+
 		-
 			message: '#^Unreachable statement \- code above always terminates\.$#'
 			identifier: deadCode.unreachable
diff --git a/src/DatabaseDriver.php b/src/DatabaseDriver.php
index b56d9229..81885d02 100644
--- a/src/DatabaseDriver.php
+++ b/src/DatabaseDriver.php
@@ -504,8 +504,12 @@ public function __destruct()
      *
      * @since   2.0.0
      */
-    public function alterDbCharacterSet(string $dbName)
+    public function alterDbCharacterSet($dbName)
     {
+        if ($dbName === null || !is_string($dbName) || $dbName === '') {
+            throw new \RuntimeException('Database name must not be null and a non empty string.');
+        }
+
         $this->setQuery($this->getAlterDbCharacterSet($dbName));
 
         return $this->execute();