-Consider the following table definition, where the primary keys are underlined. Give an expression in relational...

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Question

-Consider the following table definition, where the primary keys are underlined. Give an expression in relational...

-Consider the following table definition, where the primary keys are underlined. Give an expression in relational algebra for each of the following queries.

Athlete (aID integer, aName string, ranking integer, age integer)

Event (eID string, eName string, eLocation string)

Competes (aID integer, eID string, sport string, year integer)

3. Find the names of the events an athlete named Dennis competed in (aName = ‘Dennis’)

4. Find the names of the athletes who have competed in at least one Event

5. Find the names of athletes who have competed in ‘XGames’ or ‘Dew Tour’

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Answer 1

Answer #1

If you have any doubts, please give me comemnt...

3. Find the names of the events an athlete named Dennis competed in (aName = ‘Dennis’)

_eName(Event Completes (_{aName =
'Dennis'} (Athlete)))

4. Find the names of the athletes who have competed in at least one Event

_aName(Athlete Completes)

5. Find the names of athletes who have competed in ‘XGames’ or ‘Dew Tour’

_aName(Athlete Completes (_{eName='XGames'
eName='Dew
Tour'}(Event)))

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Answer 2

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-Consider the following table definition, where the primary keys are underlined. Give an expression in relational...

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