Using view layer in database system for zero downtime upgrade

Methods, systems, and computer-readable storage media for providing a first access schema in a view layer of the database system, the first access schema including first database objects and projection views, each projection view corresponding to a second database object of second database objects in a data persistency, transitioning access of sessions of an application from the data persistency to the first access schema, executing at least a portion of the maintenance procedure in the database system, the at least a portion of the maintenance procedure changing one or more second database objects within the data persistency, creating a second access schema, and transitioning access of the sessions of the application from the first access schema to the second access schema, transitioning access of the sessions of the application from the second access schema to the data persistency, and removing the second access schema from the database system.