Designing Records

Programs often use information about real-world objects

• usually only a small subset of all possible information
  • For example, the number of things you can record about a person is almost limitless, but for any particular purpose only a few things are relevant.
• part of design process is to select the appropriate subset
  • For example, a fitness club may need to know the name, phone number, sex, age, and weight of its customers.
• would use a record to combine components

To design a record:

• identify the items of data that are relevant in this  application
• use a data structure diagram to show the relevant information
  • decide on names for the overall structure, and for the individual fields
• determine the data types of the fields

Fitness club example:

	name	: names;	-- string sub-type
	phone	: phones;	-- string sub-type
	sex	: sexes;	-- enumerated type
	age	: ages;		-- integer sub-range
	weight	: weights;	-- float sub-type