DB Ex 6. You have just started a new job at the bank. This is a schema of the database consists of 5 tables:

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Myron Nichols
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1 DB Ex 6 Due date: Thursday :55 Submission Instructions: This exercise consists of programming in PL/pgSQL and Java (using JDBC), and should be submitted electronically, via the submission link on the course homepage. Please run your code one more time just before submission to check that it works! Submit your exercise as a zip file containing all the necessary files. PL/pgSQL: You have just started a new job at the bank. This is a schema of the database consists of 5 tables: 1. Customers(AccountNum:integer, CustomerID:integer, CustomerName:varchar, CustomerPassword:varchar, AccountStatus:varchar, Overdraft:real): This table holds all the customer data of an account that was opened in the bank, where The field AccountNum is defined as a serial primary key. In other words, when inserting rows into this table, if the AccountNum is not specified, it will automatically get as a default value the next available integer (starting at 1). See also for more details. The field CustomerID, which represents the customer s id, is constrained to be unique in the table definition. In other words, each customer can have only one bank account. AccountStatus is contains either the value open or close, indicating whether the account described is open or closed. Overdraft is a non-positive double which indicates the allowed overdraft of the current account. For example, if Overdraft is 0, the customer is allowed no overdraft, while if Overdraft is -1000, the customer can be in overdraft of 1000 sheckels. 2. Actions(ActionNum:integer, AccountNum:integer, ActionName:varchar, ActionDate:date,,(עו"ש) Amount:real): The table lists all the actions that were made in the current account where ActionNum is a serial primary key AccountNum is the number of the account in which the action was performed ActionName is one of the following four values: receive which indicates that money was added to the account (e.g., a salary was paid, a check was depositied) payment which indicates that money was deducted from the account (e.g., a credit card or check payment, cash withdrawal) saving which indicates that the customer has opened a savings account (depositing the money indicated in Amount into the savings account)

2 close which indicates that the customer has closed an account, and withdrawn all money in the account (i.e., Amount should be precisely -1 times the balance of the customer s account) If the ActionName is receive the field Amount has a positive number. Otherwise, it is negative. 3. AccountBalance(AccountNum:integer, Balance:real): This table contains, for each open account, the current balance of the account. All actions in the table Actions are reflected in this table. 4. Savings(SavingNum:integer, AccountNum:integer, Deposit:real, DepositDate:date, NumOfYears:integer, Interest:real): The table holds the saving plans of an account. Each savings plan is associated with an amount (the value of Deposit). This amount deposited by the customer upon opening the account, and again, once a year, for NumOfYears years. Each savings plan is also associated with an interest rate, which is a number between 0 and 1. (More details about the interest are appear later in this exercise, in the section on JDBC). Note that a single AccountNum can have several saving plans. Note also that Deposit and NumOfYears are positive numbers, and SavingNum is a serial primary key. 5. Top10Customers(AccountNum:integer, Balance:real): This table holds account numbers of the 10 richest customers in the bank (according to the AccountBalance table), along with their current balance. (Thus, every row in Top10Customers appears in AccountBalance, but not vice-versa.) The goal of this table is to allow the bank manager to always know who his best customers are, in order to give proper attention to those customers. Therefore this table must always be up to date. You can assume that there are foreign key constraints defined on the tables where this is natural, e.g., every AccountNum in the tables appears in Customers, etc. Also, none of the fields in any of the tables can have null values (this is also ensured by the table definitions). We have provided a file named createtables.sql with the table creating commands. Please download this from the course homepage and use while developing your solution. Write the following functions each in a different file. You should also hand in a file dropfunctions.sql that deletes all functions and triggers created: 1. newcustomer(customerid, CustomerName, CustomerPassword, Overdraft) which accepts an id, name, password, and amount of allowed overdraft and does the following: If the CustomerID does not appear in the table Customers, a new row is added to the table Customers. Note that the account status should be open. In addition, a row should be added to the table AccountBalance with a balance of 0 for the account, and the new AccountNum should be returned by the function.

3 If the CustomerID appears in the table Customers, with the status close, you should update the row with the given CustomerName, CustomerPassword and Overdraft, and change the AccountStatus to open. You should also add a row to the table AccountBalance with a balance of 0 for the account and should return the AccountNum associated with the CustomerID If the CustomerID appears in the table Customers, with the status open, no change should be made, and -1 should be returned. Write this function in a file named newcustomer.sql. 2. closecustomer(customerid) which accepts a CustomerID and deletes the customer s rows from AccountBalance, Savings, and Top10Customers, and changes the customer AccountStatus to close in the table Customers. The function returns the closed associated AccountNum, or -1 on error (e.g., if the customer s account is already closed). Write this function in a file named closecustomer.sql. 3. doaction(customerid, ActionName, ActionDate, Amount) which receives a CustomerID, ActionName, ActionDate and Amount, and adds a row to the Actions table, updates the AccountBalance table and returns the ActionNum created for this action, or -1 if the action wasn't added. Write this function in a file named doaction.sql. 4. newsaving(customerid, Deposit, DepositDate, NumOfYears, Interest) which adds a row to Savings and Actions and updates the balance of the account (as money has been taken from the account and deposited in the savings plan). The function returns the SavingNum created for this plan, or -1 if the saving wasn't added. Write this function in a file named newsaving.sql. Note: Once a customer opens a savings account they must make a deposit to it once a year. The first deposit (when the savings plan is opened), is made using the action saving as described above. The remaining deposits will be made with the action payment. However, there is no need in this exercise to ensure that these deposits are indeed made. Note that in all functions you should ensure that the input CustomerID you receive appears in the Customers table with status open. You can assume that all the updates, inserts and deletes on the database tables are done using the functions above. You are asked to ensure the consistency of the tables of the database (using triggers): a) Rows cannot be deleted from the AccountBalance table if the value of Balance is not zero. If the value of Balance is positive you should update the Actions table directly, by inserting a row with the close Action (and the correct amount of money to bring the balance to 0) and enable closing the account. If the balance is negative, the account should remain open (i.e., customers cannot close an account if they are in overdraft) and this should be accomplished by raising an exception. Write this trigger in a file named triggera.sql.

4 b) Before updating the Balance in the AccountBalance you should check that the new balance will remain consistent with the allowed Overdraft (from the Customers table). If the balance will be below the allowed overdraft, the action that caused this change should be rejected, by raising an exception. Write this trigger in a file named triggerb.sql. c) Rows can only be added to Actions and to Savings if the given date is equal to the current date. If an attempt is made to add a row with a different date, the date should be overwritten with the current date. Write this trigger in a file named triggerc.sql. d) Top10Customers should always contain the 10 richest customers (among the customers with open accounts, that have a positive balance), according to the AccountBalance table. (We ignore Savings when determining the richest customers.) In case of ties (i.e., if there is more than one customer with the tenth highest account balance) the table will contain all tied customers. Thus, for example, if there are twenty customers c 1,, c 20 with the balance of 1000 for customers c 1,,c 14 and a balance of 500 for the remaining customers, all 14 customers c 1,,c 14 will appear in Top10Customers. You should ensure that the table is up-to-date holds regardless of any inserts/deletes/updates in any of the tables in the database. Thus, whenever a modification that can affect the balance of an account is done to the database, you should update Top10Customers so that it still contains the 10 richest customers. Write this trigger in a file named triggerd.sql. For your convenience, you may want to define additional functions that will be used in several functions or triggers. You should define these in the file helperfunctions.sql. We will always load this file before loading any other of your functions or triggers. JDBC: Finally, the bank wants to offer its customers a convenient way to calculate their savings. You should write a class called CheckMySavings (in a file called CheckMySavings.java). This class must have at least the following methods: public void init(string username) public void close() public double checkmysavings(int AccountNum, Date opendate) The function init of this class should receive a username (which will be used in the connection string to connect to the database). When you test your own program, you will call this function with your username. However, in our testing, we will call this function with our db course username to test your program over our database. The function init will be called by us immediately after an instance of

5 checkmysaving is created. It is init's responsibility to make all the necessary initializations including the DB connection. The function close should close all connections. It will be called at the end of the execution. Finally, in order to calculate the saving of an account given its AccountNum and an opendate, you should sum all the saving plans of the account (and return the value) according to the following: 1. A saving plan hasn't completed: meaning, DepositDate + NumOfYears > opendate, then the amount of the saving the customer receives is the Deposit*x where x is the number of years that have elapsed between DepositDate and opendate. For example, if DepositDate = 1/1/2015, NumOfYears = 3 and opendate = 1/12/2015, the value of this savings plan is Deposit if DepositDate = 1/1/2014, NumOfYears = 3 and opendate = 1/12/2015, the value of this savings plan is 2 * Deposit (as the yearly deposit has been put into the savings plan twice) Note that because the saving plan hasn't completed the customer loses the interest he could have gained. 2. A saving plan has completed: meaning, DepositDate + NumOfYears opendate, then the amount of the saving is: f(deposit, numofyears) = deposit*(1+interest) numofyears = 1 (deposit + f(deposit, numofyears-1))*(1+interest) otherwise In case of an exception print an informative one line description of what went wrong and exit with return value of -1. In your answer you can use deprecated functions of Java's Date class. Note: 1. Carefully review the lectures about PL/pgSQL and JDBC before starting. 2. You can assume legal input for all tables: correct data types and no null values. 3. We will take off points for style only in extreme cases. No documentation is required unless you do something very special. 4. Pay attention to correct naming of functions, input variables, and files. Pay attention to correct usage of functions, valid zip file, and that everything works properly. 5. We do not have efficiency requirements. However, if your program does not complete even after a reasonable amount of time, your program may fail some of our automatic tests. 6. Please post any exercise related questions to the forum so that they can benefit the group. 7. While testing your program make sure to close all connections to the database at the end of your program! Failing to do so will cause all available connections to be expended; this means that nobody will be able to connect to the database. Good Luck!

University of Gujrat Lahore Sub Campus

University of Gujrat Lahore Sub Campus Assignment # 4 Advance Programming Techniques (CS 303) BS Computer Science Fall 2018 Date Issue: 05-12-2018 Due Date: 14-12-2018 (Friday) before 09:00 PM Instructions: