The drone club database contains the two record types in Fig. 1. A pilot may make many flights, but every flight is made by one registered pilot. The club w...
Question 1 Report
The drone club database contains the two record types in Fig. 1. A pilot may make many flights, but every flight is made by one registered pilot. The club wants to delete a pilot only after all linked flight records have been checked.
(a) State how many Flight records can link to one Pilot record. [1]
(b) Give the name of the rule that prevents a Flight record containing an unknown PilotNo. [1]
(c) State one reason why this rule improves the database. [1]
(d) Give a suitable data type for Duration measured in whole seconds. [1]
Answer Details
The relationship shown is one-to-many: a Flight must refer to one existing Pilot, while a Pilot can have multiple Flight records.
- (a) One Pilot can link to many, including zero or more, Flight records. [1]
- (b) The rule preventing an unknown PilotNo in Flight is referential integrity. [1]
- (c) Referential integrity prevents orphan records and keeps linked data valid. [1]
- (d) Duration in whole seconds should use an Integer (number) data type. [1]
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