1. A computer-implemented method of truncating data from a multi-tenant database that maintains database objects for a plurality of different tenants, each database object in the multi-tenant database being identified by a unique combination of a key prefix and a tenant identifier, the method comprising: maintaining an entity definition table having a plurality of metadata entries corresponding to the database objects, including a metadata entry for an existing database object, the metadata entry comprising a tenant identifier for a particular tenant associated with the existing database object, an entity name for the existing database object, and an old key prefix for the existing database object; obtaining an instruction to remove all data from the existing database object; and in response to obtaining the instruction, updating the metadata entry to replace the old key prefix with a new key prefix that is not currently associated with any other database object for the particular tenant, wherein updating the metadata entry results in an updated database object that is identified by the new key prefix and the tenant identifier.