Databases
Flat file databases
Database- a persistent store of organised data
Flat file- this is a type of database which only has one 2D table. It contains records (rows) and fields (columns)
Problems with flat files:
-Redundancy- data becomes inconsistent if there are duplicates i.e. if data is changed in one place it won't change elsewhere
-Unproductive maintenance, because of data/application dependency- if one is changed, the other one has to be changed too
-Slow to search
-Inefficient storage space (because of redundancy)
Example: list.csv
name1,date1,time1
name2,date2,time2
Relational database
Relational database- uses tables containing related data
Entity- a real-word object about which we would want to store data
Attribute- describes an entity
Field- a single piece of data in a database (a column)
Record/tuple-all of the data about a person or thing (a row)
Primary key- field(s) which uniquely identify a record in a database
Foreign key- used to link one table to another, it always appears on the 'many end'
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Data selection
The 2 methods of data selection are SELECT (in SQL) and Query by example (QBE), in software like MS Access
Data Capture
Data capture uses software, which uses hardware e.g. an OCR uses needs a camera
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Computer Science Reviews (A level)
Non-FictionComputing First published 4th December 2021 Finished 13th August 2022
