Question 1
Write a function (called total_cost) that returns the total cost of an item after the tax has been added to the product. The function has two IN parameters Customer ID and Item ID and returns a number as a result of the function execution. If a Customer ID or Product ID or STATE does not exist in the relevant tables the function should return NULL as the result. You need to return the NULL result explicitly and not as a part of the cost calculation. The function calculates cost of an item based on the percentage charged for the state the customers address is in.
Write an SQL statement that displays customer details (ID, First Name, Last, Name, State) and total to be paid for each customer for product in the BB_PRODUCT table whose ID is 4 by calling the total_cost function.
Write a procedure (called report_on_products) that takes a single IN parameter Product ID and creates a report to the screen as follows. For every customer in the table create a report using the DBMS_OUTPUT module to print the Customer Last Name, First Name,
State, Product Description, Product Cost, Tax, total cost by calling the total_cost function.
After processing all the customers display the following information.
Total customers processed XX and total tax calculated $XX.YY.
The tax calculated is the sum of tax that each customer would have had to pay in that product.
Call the procedure from an anonymous block and capture the results.
Question 2
The Brewers Company is concerned about possible unauthorised changes to customer orders that may compromise the company's profit. You will create a database trigger to monitor such changes to some important columns in the BB_BASKET table.
1. Create a copy of the BB_BASKET table in your own schema by using the following command:
CREATE TABLE MY_CUSTOMER AS SELECT * FROM BB_BASKET;
2. Also create a table to store change logs (call the table BB_CHANGELOG) to hold the following fields IDBASKET, QUANTITY, SUBTOTAL, TOTAL and LOG_DATE DATE. You will need to refer to the relevant table for field types and sizes. The LOG_DATE field will contain the system date.
3. Create a database trigger with the following specification:
• fires AFTER an UPDATE on MY_CUSTOMER table.
• fires if there is any change to QUANTITY, SUBTOTAL or TOTAL columns of the MY_CUSTOMER table.
• fires for each row.
• inserts a first row: the affected IDBASKET column, the OLD values of the QUANTITY, SUBTOTAL and TOTAL columns and the current
date into the table BB_CHANGELOG.
• inserts a second row: the affected IDBASKET column, the NEW values of the QUANTITY, SUBTOTAL and TOTAL columns and the current date into the table BB_CHANGELOG.
4. Test the trigger with the following specification:
• Go ahead and make a change to MY_CUSTOMER table by issuing the following command:
UPDATE MY_CUSTOMER
SET QUANTITY = 13, TOTAL = 25000
WHERE IDBASKET = 13;
5. Now, select all rows from the BB_CHANGELOG table. This should display the OLD and NEW values of the changes you made due to firing of the trigger. Output all the rows of CUSTOMER_CHANGELOG table.
Question 3 (40 marks)
This question has a few section (procedures and functions) described. You are free to write helper procedures or functions but they will have to have high cohesion and low coupling (do one thing only and not be reliant on external values).
1) Create a PL/SQL procedure called shopping_month which has an in parameters for the year and the month. The procedure will display to the screen the following information for each basket created (DTCREATED) for that year/month. The information needs to be retrieved using an explicit cursor.
Basket BASKEID has a total of BASKET_TOTAL plus SHIPPING total cost of order BASKET_TOATL_PLUS_SHIPING
2) Write a function called total_shipping which takes in the date parameter and calculates the cost of shipping for all the baskets which have been created in that year/month.
3) Write a procedure called uncommitted_month which reports on all the baskets created but where the order has not been placed (ORDERPLACED) for all the baskets in the table. The output should be as follows.
Currently there are COUNT numbers of orders created but not finalized with a total of $AMOUNT.XX and shipping cost of $SHIPPING.XX.
4) Write a procedure called report_shopping_totals that will produce the following output in the format specified bellow. The procedure needs to use explicit cursor/s for each year starting with the oldest year and produces a summary of the shopping for that month.
The years and month output needs to be in ascending order.
Example dummy output only as a guideline. You will need to replace the uppercase fields with the necessary values
Year YYYY
January
Basket BASKEID has a total of BASKET_TOTAL plus SHIPPING total cost of order BASKET_TOATL_PLUS_SHIPING
Basket BASKEID has a total of BASKET_TOTAL plus SHIPPING total cost of order BASKET_TOATL_PLUS_SHIPING
Total Shipping for the month $SHIPPING.XX
March
Basket BASKEID has a total of BASKET_TOTAL plus SHIPPING total cost of order BASKET_TOATL_PLUS_SHIPING
Total Shipping for the month $SHIPPING.XX
Year YYYY
February
Basket BASKEID has a total of BASKET_TOTAL plus SHIPPING total cost of order BASKET_TOATL_PLUS_SHIPING
Total Shipping for the month $SHIPPING.XX
Total number of baskets processed COUNT total income of all orders is $AMOUNT.XX total shipping cost $SHIPPING.XX.
There are COUNT numbers of orders created but not finalized with a total of $AMOUNT.XX and shipping cost of $SHIPPING.XX.
The anonymous block should only have to call report_shopping_totals which will contain the logic to display the requested output. Your solution for the final output needs to use the functions and procedures defined previously. Due to the data in the tables you will only have one year on the report. Your code needs to work when more data is added.