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DBG Queries in relational algebraTania Cerquitelli Relational algebra

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Relational algebra

Queries in relational algebra

Tania Cerquitelli

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Exercise n. 1

Find the codes of patient that have bought at least two drugs of the same category in the same day.

DRUG (DrugCode, DrugName, Category)

PATIENT (PatientCode, PatientName, BirthDate) DOCTOR(DoctorCode, DoctorName)

SALE(DrugCode, PatientCode, Date, DoctorCode, Quantity, Amount)

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Exercise n. 2

Find the codes of customers that reserved only resorts located in their country.

CUSTOMER (CustCode, CustName, Gender, AgeRange, CustCountry) VACATION-RESORT (ResCode, ResName, ResType, Location, ResCountry)

RESERVATION(CustCode, StartDate, EndDate, ResCode)

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Exercise n. 3

Show the code and name of products of the “Puma” brand that have been on sale at least twice in the same shop with a discount higher than 60%.

PRODUCT(PCode, PName, Brand, Price) SHOP(SCode, SName, DateOpening, City)

SALE(PCode, SCode, SaleStartDate, Duration, DiscountPercentage)

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