10916334
Description
Flashcards by samantha routledge, updated more than 1 year ago
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Created by samantha routledge
over 8 years ago
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| Question | Answer |
| Normalisation | A mathematical technique for analysing data and is a staged process which improves the database design at each stage. At this level we need to look at normalisation as a three stage process called 1st normal form, 2nd normal form and 3rd normal form. |
| Data redundancy | Refers to the uneccessary duplication of data. A company may hold its data in different files. This is wasteful beacuse some data may need to be inputted twice. |
| Data consistency | The same data has exactly the same value and formatting throughout the system. By using one file to hold a central pool of data this means if information is changed in one file it does not need to be changed in another. |
| Data integrity | The correctness i.e. the extent to which it turthfully represents original information. |
| Data independence | The data and the applications/programs used to access it are seperate. |
| Database security | Hirearchy of passwords - limits users to various parts of the program. A receptionist would only have access to basic patient details whilst a doctor would see all infomration on the patient. |
| Database security | Access rights - to parts of the program only certain users can access and change data. A nurse would see all the information on a patient but be unable to alter the drug dose details whilst a doctor could. |
| Database security | Storage of data seperate from the programs - this means that the data is not stored with the program that it is using. The data is shielded by the database management system which determines what data the program is allowed to see. |
| Data warehouse | is a larger database used to store a organisations historical data which is used by a Management Information System (MIC) to extract information |
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