Question

Using this relations scheme:

1.. products FK product Code product and productLine productScale product Vendor product Description QuantityinStock buy Price MSRP PK 1.1 FK FK order Details 1.." Order Number product Code QuantityOrdered price Each OrderlineNumber PK employees employee Number lastame firstName extension email officeCode reportsTo job Title PK FK FK 0..1 1.. 0.1 offices officeCode city phone addressLine1 addressLine2 state country postal Code territory PK 1.. FK customers customer Number customer Name contactLastName contactFirstame phone addressLine1 addressLine2 city state postal Code country salesRepEmployee Num ber CreditLimit PK 1.1 1.." FK orders orderNumber order Date requiredDate shippedDate status comments customer Number PK 1.1

write these queried in relational algebra

2.List productCode, productName, and productVendor for each product that has never been ordered in June. Remember that we have the month function that returns the number of the month component of a data, and January is month number 1.

3.List the Customers that did not Order any products in 2015.

4.List all CustomerNames who have never had an order go to the ‘Shipped’ status.

Answer 1

2.

$\pi$_{products.productCode, productName, productVendor}( _{month(orderDate) != 6} (products $\Join$ orderDetails $\Join$ orders ) )

3.

$\pi$_{customers.customerNumber, customerName} ( _{year(orderDate) != 2015} (customers $\Join$   orders ) )

4.

$\pi$ _customerName ( _{status != 'Shipped'} (customers $\Join$   orders ) )

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