Access control for groups of related data items

摘要

Access to groups of related items which are accessible by multiple processes in a computer system is controlled, in response to determining 106 that an individually accessed data item is part of a group, by storing 107 the message sequence number as a locking key in the group lock key field (77 Figure 7), and setting 108 the group locked flag bit to complete the group locking process. Further access by a process to any items of a group for which the group locked flag is set is denied unless the message sequence number held in the browse cursor key field matches (207, Figure 9) the group locked key. The system is particularly applicable to a messaging and queuing system in which messages are logically grouped and yet may be individually destructively retrieved.