1. A computer-implemented method for performing backup of a database, the method comprising: maintaining a database system storing a plurality of database objects; receiving, by the database system, a first backup command; executing the first backup command, comprising backing up a set of database objects; receiving an alter backup command identifying a database object and specifying that the identified database object be added to database objects backed up by subsequent backup commands, the alter backup command specifying a criteria; executing the alter backup command; receiving a second backup command responsive to executing the alter backup command, wherein the second backup command specifies an incremental backup; and executing the second backup command, comprising: evaluating the criteria to determine whether the criteria is satisfied; responsive to determining that the criteria is satisfied, modifying the set of database objects to include the identified database object; and backing up the modified set of database objects, wherein the data backed up by the second backup command comprises changes to one or more database objects that were backed up by the first backup command and a full copy of the identified database object.