CS157b
Chris Pollett
May 4, 2020
Below are three common techniques for integrating data source, we will go into them in more detail after the quiz.
Which of the following statements is true?
AutosWarehouse(serialNo, Model, color, autoTrans, dealer)
INSERT INTO AutosWarehouse(serialNo, Model, autoTrans, dealer) SELECT serialNo, model. color, autoTrans, "Dealer 3" FROM Cars;
AutosMediator(serialNo, Model, color, autoTrans, dealer)
SELECT serialNo, model FROM AutosMediator WHERE color = 'red';for Dealer 2 which has the tables Autos(serial, model, color) and Options(serial, option), the mediator would send the query to the Dealer 2's wrapper which would compute the query:
SELECT serial, model FROM Autos WHERE color = 'red';On the other hand, the same query sent to Dealer 3 would result in the query:
SELECT serialNo, model FROM Cars WHERE color = 'red';
SELECT * FROM AutosMediator WHERE color = '$c' => SELECT serialNo, model, color, autoTrans, 'dealer3' FROM Cars WHERE color = '$c'
Sales(serialNo, date, dealer, price) Autos(serialNo, model, color) Dealers(name, city, state, phone)
SELECT state, AVG(price) FROM Sales, Dealers WHERE Sales.dealer = Dealers.name AND date >= '2006-1-04';