A system may include a shared storage data store containing a first version of entities with original content and a local tenant storage data store to contain information associated with a tenant's application server. A database interface agent may enter a copy-on-access mode and maintain materialization and modification flags. The agent may then initiate an upgrade process during which the first version of the entities are utilized by the application server. The agent may then enter a copy-on-write mode and delete, from the local tenant storage data store, entities having flags that indicate the table was migrated but did not receive customer data. The structure of the remaining entities may then be updated in view of the structure of the second version of the entities. Finally, the content of the entities may be updated in view of the content of the second version of entitles and previously received customer data.