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In computer systems security, role-based access control (RBAC) [1][2] or role-based security[3] is an approach to restricting system access to authorized users, and to implementing mandatory access control (MAC) or discretionary access control (DAC). Role-based access control is a policy-neutral access control mechanism defined around roles and ...
Two-phase commit protocol. In transaction processing, databases, and computer networking, the two-phase commit protocol (2PC, tupac) is a type of atomic commitment protocol (ACP). It is a distributed algorithm that coordinates all the processes that participate in a distributed atomic transaction on whether to commit or abort (roll back) the ...
ANSI-SPARC Architecture. The ANSI-SPARC three-level architecture. The ANSI-SPARC Architecture (American National Standards Institute, Standards Planning And Requirements Committee), is an abstract design standard for a database management system (DBMS), first proposed in 1975. [1]
Two-phase locking. In databases and transaction processing, two-phase locking ( 2PL) is a pessimistic concurrency control method that guarantees conflict-serializability. [ 1][ 2] It is also the name of the resulting set of database transaction schedules (histories). The protocol uses locks, applied by a transaction to data, which may block ...
Rule 11: Distribution independence: The end-user must not be able to see that the data is distributed over various locations. Users should always get the impression that the data is located at one site only. Rule 12: The nonsubversion rule: If a relational system has a low-level (single-record-at-a-time) language, that low level cannot be used ...
Users can exist without schema objects, but an object is always associated with an owner (though that owner may not have privileges to connect to the database). With the 'shared-everything' Oracle RAC architecture, the same database can be opened by multiple servers concurrently. This is independent of replication, which can also be used ...
Database transaction schedule. In the fields of databases and transaction processing (transaction management), a schedule (or history) of a system is an abstract model to describe the order of executions in a set of transactions running in the system. Often it is a list of operations (actions) ordered by time, performed by a set of transactions ...
Relational database. A relational database (RDB[ 1 ]) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. [ 2 ] A database management system used to maintain relational databases is a relational database management system (RDBMS). Many relational database systems are equipped with the option of using SQL ...