Patent attributes
Implementations include actions of initiating a procedure on an application that interacts with a database system having a start schema, through which a first version of the application interacts with tables, providing a bridge schema including table views to each table of the start schema, switching a first version of the application to interact through the bridge schema, creating a shadow field in a table, the shadow field corresponding to a field of the table that is to undergo a change during an upgrade from the first version to a second version, providing a trigger in the start schema, the trigger executing a transformation between the field and the shadow field during the upgrade, modifying the table in the start schema to a target structure to change a parameter of the shadow field or the field of the table, and switching the second version to interact through the start schema.