Answer Happy

Question 12 3 pts Consider again the following relation about public transport users tapping on and off from trains, buses and ferries with their Opal Card: CardEvents (id: integer, day: date, card: integer, mode: text, tap_on: timestamp, tap_off: timestamp) The Sydney public transport network records about 1.5 million trips each day, where each trip shows in the given dataset as one entry with corresponding tap_on and tap_offtimestamps and the day when a customer started the trip, the card number used, and which mode of transport was used ('bus', 'lightrail', 'train' or 'ferry'). We have data since April 2014. Assume the Card Events relation is stored as an unordered heap file for which the only index is an unclustered B+-tree index on field day. If you want to retrieve all trip events within a certain time range (e.g. day BETWEEN '2020-04-01' AND '2020-07-31'), is using the index always the best alternative? Briefly explain.