A computer system receives a data collection and creates an administration table. A main process locks the data collection against unauthorized access using an association, in a lock table, between it and a lock identifier required for data collection access by processes. The main process divides the data collection into subgroups. The lock identifier and each subgroup are forwarded to one of the processes; the subgroups being parallel processed by recipient processes that access and update the data collection using the lock identifier, and set the lock identifier and update the administration table regarding the processing done by the recipient process, the administration table being common to all of the subgroups. After the recipient processes, the data collection is unlocked by the main process by removing the association between the data collection and the lock identifier in the lock table.