diff --git a/install/sql/alter_tables/1.9.20/mysql/DB.1.9.20/step1/db_schema_update.sql b/install/sql/alter_tables/1.9.20/mysql/DB.1.9.20/step1/db_schema_update.sql
index e3d151c2cc..16f0acda29 100644
--- a/install/sql/alter_tables/1.9.20/mysql/DB.1.9.20/step1/db_schema_update.sql
+++ b/install/sql/alter_tables/1.9.20/mysql/DB.1.9.20/step1/db_schema_update.sql
@@ -22,8 +22,8 @@ ALTER TABLE /*prefix*/users MODIFY password VARCHAR(255) NOT NULL default '';
 
 -- 
 ALTER TABLE /*prefix*/testplan_platforms ADD COLUMN active tinyint(1) NOT NULL default '1';
-ALTER TABLE /*prefix*/platforms ADD COLUMN  enable_on_design tinyint(1) NOT NULL default '0';
-ALTER TABLE /*prefix*/platforms ADD COLUMN  enable_on_execution tinyint(1) NOT NULL default '1';
+ALTER TABLE /*prefix*/platforms ADD COLUMN  enable_on_design unsigned tinyint(1) NOT NULL default '0';
+ALTER TABLE /*prefix*/platforms ADD COLUMN  enable_on_execution unsigned tinyint(1) NOT NULL default '1';
 
 --
 ALTER TABLE /*prefix*/nodes_hierarchy ADD INDEX /*prefix*/nodes_hierarchy_node_type_id (node_type_id);