Flashcards
computing
Cards in this deck (10)
- 1What is a database?an organised set of data held in a computer.
- 2Advantages of flat-file databases...All records are stored in one place
Easy to understand
Simple sorting and filtering can be carried out
Can use a standard spreadsheet to store it
Alternatively, you can use a single table in a DBMS to store it - 3disadvantages of flat-file databases...1. Potential duplication.
2. Non-unique records.
3. Harder to update.
4. Inherently inefficient.
5. Harder to change data format. - 4Relational databasesA type of database created to overcome the problems of flat-file databases, this type of database holds data over a number of tables, records held within these tables are linked to records held in other tables.
- 5Advantages of relational databasesData is only stored once
complex queries can be carried out
better security
care for future requirements - 6validationValidation aims to make sure that data is sensible, reasonable, complete and within acceptable boundaries.
- 7range checkA range check is commonly used when you are working with data which consists of numbers, currency or dates/times.
- 8type checkA type check will ensure that the correct type of data is entered into that field.
- 9check digitThis is used when you want to be sure that a range of numbers has been entered correctly for example a barcode or an ISBN number
- 10length checkA length check could be set up to ensure that exactly 11 numbers are entered into the field. This type of validation can't check that the 11 numbers are correct but it can ensure that 10 or 12 numbers aren't entered.
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- Flashcards on computing, created by ollyfreer on 29/04/2015.
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- ollyfreer
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