Database Systems. What is a database? A database is an organised store of data items.
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Transcript of Database Systems. What is a database? A database is an organised store of data items.
![Page 1: Database Systems. What is a database? A database is an organised store of data items.](https://reader035.fdocuments.in/reader035/viewer/2022072008/56649d705503460f94a52ef6/html5/thumbnails/1.jpg)
Database Systems
![Page 2: Database Systems. What is a database? A database is an organised store of data items.](https://reader035.fdocuments.in/reader035/viewer/2022072008/56649d705503460f94a52ef6/html5/thumbnails/2.jpg)
What is a database?
A database is an organised store of data items.
![Page 3: Database Systems. What is a database? A database is an organised store of data items.](https://reader035.fdocuments.in/reader035/viewer/2022072008/56649d705503460f94a52ef6/html5/thumbnails/3.jpg)
What are the key terms associated with databases?
Query – is when you interrogate (search ) a database to find some information e.g. Search for all females in Year 8 because they need to be sent HPV injection letters.
Report – the output from a database in which the results are presented in a way controlled by the user. It is usually a formatted printout. E.g. Formatted list of pupils who study each subject to work out rooms for exams.
Import/Export – the ability of software to read and use the data produced by a different piece of software e.g. Exporting names and grades into a word processing program to produce reports.
![Page 4: Database Systems. What is a database? A database is an organised store of data items.](https://reader035.fdocuments.in/reader035/viewer/2022072008/56649d705503460f94a52ef6/html5/thumbnails/4.jpg)
What are the key terms associated with databases?
Consistency –data should be stored in a consistent format
Redundancy – data which is stored more than once unnecessarily is called redundant data
Independence – the data is stored separately from the applications that use it
![Page 5: Database Systems. What is a database? A database is an organised store of data items.](https://reader035.fdocuments.in/reader035/viewer/2022072008/56649d705503460f94a52ef6/html5/thumbnails/5.jpg)
What is a flat file database?
A flat file database contains only one table of data. These could be set up in either database software or spreadsheet software.
• What is a relational database?
A relational database is a large collection of data items(tables) with relational links between them.
![Page 6: Database Systems. What is a database? A database is an organised store of data items.](https://reader035.fdocuments.in/reader035/viewer/2022072008/56649d705503460f94a52ef6/html5/thumbnails/6.jpg)
What are the problems with a flat file database?Redundancy• Large amounts of duplicated data• Makes data entry slower• Uses disk space
Reduced data integrityMore likely to be inaccurate! Due to:• Data input errors• Inconsistent data entry
Difficult to update• If entries change all instances have to be updated
Security• All users have access to the same set of data
![Page 7: Database Systems. What is a database? A database is an organised store of data items.](https://reader035.fdocuments.in/reader035/viewer/2022072008/56649d705503460f94a52ef6/html5/thumbnails/7.jpg)
Database security
Hierarchy of passwords – this limits users to various parts of the program. E.g. A receptionist would only have access to basic patient details but a Doctor would be able to see all the information.
Access rights – only certain users can access and change data. E.g. Nurse would see information on a patient but be unable to alter drug doses etc.
Independence – the data is stored separately from the applications that use it