diff --git a/classes/PHPixie/Migrate/Driver/PDO.php b/classes/PHPixie/Migrate/Driver/PDO.php
index 0ab7028..18eb264 100755
--- a/classes/PHPixie/Migrate/Driver/PDO.php
+++ b/classes/PHPixie/Migrate/Driver/PDO.php
@@ -99,7 +99,7 @@ protected function column_definition($def, $with_keys = true) {
 		if (isset($def['default']))
 			$str.= "DEFAULT {$def['default']} ";	
 		
-		if ($db_type = 'mysql' && $type == 'id')
+		if ($db_type == 'mysql' && $type == 'id')
 			$str.= "AUTO_INCREMENT ";	
 			
 		if (!empty($def['primary'])&&$with_keys)
@@ -145,4 +145,4 @@ protected function quote($str){
 		return $quote.$str.$quote;
 	}
 	
-}
\ No newline at end of file
+}