Databases
- Created by: millard
- Created on: 25-04-16 17:00
View mindmap
- Databases:
- A persistent and organised store of data
- DBMS
- As data can be separated from the application it allows for: more users to access the data, multiple applications can run on the same data and the data structure doesn't depend on the application
- Principal features of a DBMS:
- Provide levels of security for different users (controlling who can view what)
- As data can be separated from the application it allows for: more users to access the data, multiple applications can run on the same data and the data structure doesn't depend on the application
- Allows multiple users to view the data at once
- Relational Databases:
- Modules: like macros, they add functionality to the DB
- Reports: print-out version of the DB that summaries + presents data
- Unique Identifiers
- They are Primary keys which are used to connect the tables
- Become foreign keys when they are referenced in other Tables
- By splitting data into different tables you reduce data redundancy
- Validation
- Checks that the data is reasonable, sensible and complete BUT NOT ACCURACY
- Verification is needed to check that the data is as accurate to the source document as possible
- Enter the data twice
- Checking the data on the screen against the original document
- Printout the document and check it against the source document
- Verification is needed to check that the data is as accurate to the source document as possible
- Check digit: Checks that a range of numbers have been entered in the correct order
- Lookup: DROP DOWN MENU
- Checks that the data is reasonable, sensible and complete BUT NOT ACCURACY
- DBMS MUST be able to: Create, Retrieve, Update, Delete
- DBMS
- Principal features of a DBMS:
- Provide levels of security for different users (controlling who can view what)
- Allows multiple users to view the data at once
- Principal features of a DBMS:
- DBMS
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