Methods, systems, and computer-readable storage mediums are presented for aggregating multiple values for an object using database rows. Each value added to the database for the object may include a same primary key and a unique sequence key. This allows multiple values to be added for an object concurrently by simply adding additional rows to the database table. After values have been added, a process can identify multiple rows having the same primary key and aggregate the values stored in those rows together into a single database row having the primary key. This can be done as part of a garbage-collection routine or in response to other processes attempting to add additional values for the object.