Principles of Data Storage
Computer Science: OCR A Level, topic 3.2.8
Principles of Data Storage
In any organisation, it is imperative that the data stored is as accurate as possible. A set of principles are implemented to ensure data accuracy.
Transaction processing
- A transaction on a database comprises of a series of small actions.
- For example, buying cinema tickets.
- A database management system (DBMS) has to ensure that all of the possible concurrent transactions (like multiple bookings at the same time) will leave the data in the same state as if each transaction was performed one after another.
Record locking
- Record locking is used to lock a record in a table until a transaction is completed.
- If the transaction fails, the record is unlocked for someone else to access.
Redundancy
- Databases for organisations such as hospitals, military forces and banks need to ensure they have redundancies built into their database systems.
- This means they will have multiple clone database systems all running at the same time that are all mirror images of one another.
Redundancy cont.
- Redundant systems are usually kept in geographically different places. These systems constantly monitor each other.
- If one system goes down, then other systems can take over and will update the system that has gone down.
- One of the other redundancy systems instantly takes over and continues to provide the service needed.
Test yourself on Principles of Data Storage
Which organisation would not typically use redundant systems?