Herts Aircraft Support Services (HASS) perform maintenance on commercial aircraft. They employ many mechanics, although they do employ other staff. Mechanics are considered systems specialist, such as engine, airframe, avionics, etc, if they have completed a specialist course successfully, these qualifications have to be renewed every few years to ensure the mechanic is up to date with their knowledge. HASS maintains details about: - the staff that work there including personal details - the employment history of their staff, different roles they have undertaken and promotion records - qualifications in specialist systems that mechanics have achieved, when, and the length of time it is valid for - the aircraft it has maintained - task undertaken on any aircraft and which mechanic performed it - any part/component used on a task Using the specification above, answer the following questions: a. List 4 entities identified in the specification describing the objects they contain when, and the length of time it is valid for - the aircraft it has maintained - task undertaken on any aircraft and which mechanic performed it - any part/component used on a task Using the specification above, answer the following questions: a. List 4 entities identified in the specification describing the objects they contain [8 marks] b. Describe any two relationships defining for both, the : - Name (in one direction) - Cardinality Participation ensure you detail the assumptions you make in each case [8 marks] c. Identify one of the following within any of the entities identified: A possible simple key with explanation A possible composite key with explanation