T1 Week2: Methods of organsising databases: Flatfile DB (pg 119)

1. Read pg 119 - identify three computer based methods of organiising data

• Flatfile
• Realtional
• Hypertext/hypermedia/hyperlinks

2. Read page 121 - 122 on choosing appropriate field data types. summarise what must be considered when selecting data types.
Arithmetic operations: numeric data type,
Digits: no mathematical operations:-> text data type
Dates and Times: - dates and times
Data Text: limited number of characters, cannot be indexed
Unlimited characters : Memo
Numeric data: determine if its an interger or not. -> calculates the number of possible variations, roughly each character on the key board is a bite.
Numbers: Currency or money values -> use currency data type

• Fixed point: specifies how many decimal points - rarely used, doesnt represent accurately e.g has more that 2 decimal points, reserved for specialised docs, limited representation
• Floating: use of any number of decimal, commonly used, more range, more versatile, 7 significant figures.

Sorting a text field:  ascending sort of text -> 0,1,2,3 ... A,B,C
Alpha numeric characters: e.g.
1
10
103
12
2
21

value of currency: modified forms of fixed point representation

3.  Create a data dictionary (http://bettscomputers.com/moodle/course/view.php?id=26&topic=all#datadictionaries ) for the information system you documented last week (RTA, Video Store or School). Use sample HSC question on pg 123 as a guide.