Database Systems - Definitions and Distributed Databases
- Created by: lauren778
- Created on: 10-04-18 13:53
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- Database Systems
- Database Management System
- Software used to set up a database. It holds the relationships between data and allows for data to be interrogated.
- Security
- Relational databases allow for a username and hierarchal PW system.
- Data Warehousing
- Large amounts of data stored together in a single location, for further processing.
- Used to support organisation decision making e.g. store card offers
- Data Mining
- Interrogating a data warehouse to discover patterns, trends and possible links between items of data.
- Eg. Jaeger used data mining to look into transactions and the position of items in the store. Found that most items were stolen near doors.
- Interrogating a data warehouse to discover patterns, trends and possible links between items of data.
- Distributed Databases
- Data stored on computers at different locations, but it appears as one logical database.
- Eg. A large car hire firm has offices at many airports.
- A table containing French cars is best kept in France, closest to where it is needed.
- Eg. A large car hire firm has offices at many airports.
- Advantages
- Not dependent on one central store
- Easy to back up data
- Reduces network traffic
- Faster response to local queries
- If one server fails, others can be used.
- Not dependent on one central store
- Disadvantages
- Security issues - risk of hackers
- If one server fails, no data could be obtained from it
- Comm. lines are expensive
- Greater chance of inconsistencyif data is stored and update in >1 places.
- Hard to control data spread out in different places.
- Data stored on computers at different locations, but it appears as one logical database.
- Database Management System
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