As such, constraints on both reads and writes are in support of that rule. A role can be thought of as a set of transactions that a user or set of users can perform within the context of an organization. Transactions are allocated to roles by a system administrator. The role of a pharmacist includes the transactions to dispense but not prescribe prescription drugs. Membership in a role is also granted and revoked by a system administrator.
Roles are group oriented.
For each role, a set of transactions allocated the role is maintained. In addition, each role has an associated set of individual members. The term transaction is used in this paper as a convenience to refer to a binding of transformation procedure and data storage access. This is not unlike conventional usage of the term in commercial systems. For example, a savings deposit transaction is a procedure that updates a savings database and transaction file.