Database Design 02 0.0 / 5 ? ComputingDatabasesGCSEAQA Created by: Mr_MackintoastCreated on: 18-04-17 16:12 What is concurrency? Concurrency is making a database accessible to lots of people at the same time. 1 of 8 What is transaction? Transaction is a change to the database 2 of 8 What does ACID stand for? ACID = Atomicity, Consistancy, Isolation, Durability 3 of 8 What is atomicity? Atomicity- Transaction completely carried out or not at all. If any part fails, it must return to its original state 4 of 8 What is consistancy? Consistancy is that it must not break the rules of referential integrity. Must take the database from one valid state to another 5 of 8 What is Isolation? Isolation is that no transaction must interfere with another one (e.g. two transactions cant operate on the same record at the same time) 6 of 8 What is durability? Durability is that once a transaction has been comitted it must remain so even in the case of an error or power failure. 7 of 8 What is a query? A Query is what is extracted from a database 8 of 8
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