August 1997 SD206: Systems Design (Question 4) Suggested Solutions

4.	(a) Describe, with examples, two types of data which might be captured by a system.			[4]
	One mark should be awarded for e3ach correct type of data named, and a further mark should be awarded for a satisfactory example (up to a maximum of four marks).
		Data that changes with every transaction. For example, the quantity of supplies purchased each time a retailer places an order with a wholesaler.
		Data that differentiates between the particular item being processed and all other items. For example, the inclusion on a patient's record of that individual's social security number.

	(b) Why is it important to validate data during input?			[2]
	One mark should be awarded for each valid point (up to maximum of two marks). Examples include the following:
		To ensure data accuracy.
		To avoid the need for data correction which may be difficult and/or time consuming.

	(c) Describe two types of validation and, in each case, give an example of the type of problem it can prevent.			[4]
	One mark should be awarded for each type of validation named, and a further mark should be awarded for an example of the type of problem it can prevent (up to a maximum of four marks). Examples include the following:
		Validating input transactions. This may prevent:
			Submitting the wrong data.
			Data submitted by an unauthorised person.
			Asking the system to perform an unacceptable function.
		Validating input data. This may prevent:
			Missing data.
			Incorrect field length.
			Data has unacceptable composition.
			Data is out of range.
			Data is invalid.
			Data does not match stored data.

	(d) Give two reasons why designing an effective system output is important.			[2]
	One mark should be awarded for each valid point (up to a maximum of two marks). Examples include the following:
		Output reflects the quality of the system.
		Users depend on output to accomplish their tasks.

	(e) Give four reasons why a user might require output.			[4]
	One mark should be awarded for each valid point (up to a maximum of four marks). Examples include the following:
		To monitor and control.
		To make decisions.
		To inform.
		To confirm an action.

	(f) Describe four objectives of output design.			[4]
	One mark should be awarded for each valid point (up to a maximum of four marks). Examples include the following:
		Design output to serve its intended purpose.
		Designing output to fit the user.
		Deliver the appropriate quantity of output.
		Ensure that the output is where it is needed.
		Provide the output on time.
		Choose the right output method.