Hotels(hID, name, location, phone, avgRating: integer) • Rooms(rID, hID, type, price, availability: boolean) • Bookings(bID, rID, hID, gID, startDate, endDate, totalCost: integer) • Guests(gID, name, phone, address) • Amenities(amenityID, name, description) • HotelAmenities(hID, amenityID) • HotelReviews(hID, gID, rating: integer, review)   Find the names of guests who have made more than one booking at HotelA (unique name). Using the RA expression and don't use Aggregate functions!!!

The value range of an attribute must be large enough for the index to be relevant. Except for this one use case, an index is never helpful.

The database used for this question is a very simple one with the following schema: (Primary keys are bold, foreign keys are underlined)   CUSTOMER (CustID, FirstName, LastName, City, Phone, Email) INVOICE (InvoiceNumber, CustID, Date) INVOICE_ITEM(InvoiceNumber, ItemNumber, Quantity) ITEM (ItemNumber, ItemName, UnitPrice)   When a customer makes a purchase, an invoice is created. The invoice may be for many items. For example, in a single purchase, a customer might buy 10 Back Scratchers, 4 Hair Removers and a Dog Lead. Provide relational algebra (NOT SQL) queries to find the following information. NOTE: You can use the symbols  s, P, etc., or the words’ PROJECT’, ‘RESTRICT’ etc. as you prefer.  You do not need to try to make efficient queries – just correct ones. Where you use a join, always show the join condition.   List the dates on which Homer Griffin made purchases. List the first and last names of customers who have bought “Back Scratcher” or “Hair Remover” List the first…

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