diff --git a/inc/db.php b/inc/db.php
index c405430..5fbd1ce 100644
--- a/inc/db.php
+++ b/inc/db.php
@@ -306,12 +306,15 @@ class Db extends PhpObject
 	private function getTableConstraints($sTableName)
 	{
 		//Primary key
-		$asTableConstraints = array('PRIMARY' => "PRIMARY KEY (`".self::getId($sTableName)."`)");
+		$asTableConstraints = array("PRIMARY KEY (`".self::getId($sTableName)."`)");
 
 		//Foreign keys: applied using ALTER TABLE syntax at the end to prevent scheduling CREATE TABLE queries
 
 		//Other constraints
-		if(array_key_exists($sTableName, $this->asOptions['constraints'])) $asTableConstraints[] = $this->asOptions['constraints'][$sTableName];
+		if(array_key_exists($sTableName, $this->asOptions['constraints'])) {
+			if(is_array($this->asOptions['constraints'][$sTableName])) $asTableConstraints = array_merge($asTableConstraints, $this->asOptions['constraints'][$sTableName]);
+			else $asTableConstraints[] = $this->asOptions['constraints'][$sTableName];
+		}
 		return $asTableConstraints;
 	}