MIT-Curricular/DBMS/SQL/Week6/writeup.md

1. Create a function to return total number of accidents happened in a particular year.

SQL> create or replace function total_accd
    (year in int)
    return int
    as
    total int;
    begin
    select count(report_number)
    into total
    from accident
    where extract(year from accd_date)=year;
    return total;
    end;
    /

Function created.

SQL> select total_accd(2024) from dual;

TOTAL_ACCD(2024)
----------------
               2

2. Create a procedure to display total damage caused due to an accident for a particular driver on a specific year.

CREATE OR REPLACE PROCEDURE tot_damage
    (driver IN VARCHAR2, year IN NUMBER) IS
    damage NUMBER := 0;
BEGIN
    SELECT NVL(SUM(pa.DAMAGE_AMOUNT), 0) INTO damage
    FROM participated pa
    JOIN accident ac ON pa.REPORT_NUMBER = ac.REPORT_NUMBER
    WHERE pa.DRIVER_ID# = driver
      AND EXTRACT(YEAR FROM ac.ACCD_DATE) = year;

    DBMS_OUTPUT.PUT_LINE('Total damage: ' || damage);
EXCEPTION
    WHEN NO_DATA_FOUND THEN
        DBMS_OUTPUT.PUT_LINE('No data found for the given driver and year.');
    WHEN OTHERS THEN
        DBMS_OUTPUT.PUT_LINE('An error occurred: ' || SQLERRM);
END;
/

SQL> execute tot_damage('1236',2024);
Total damage: 150

PL/SQL procedure successfully completed.

3. Create a procedure to display accident information which took place in a particular location.

SQL> CREATE OR REPLACE PROCEDURE accident_info(location_value IN VARCHAR2) IS
BEGIN
    FOR accident_rec IN
    (SELECT * FROM accident WHERE LOCATION = location_value) LOOP
        DBMS_OUTPUT.PUT_LINE('Report Number: ' || accident_rec.REPORT_NUMBER || 
                             ', Date: ' || TO_CHAR(accident_rec.ACCD_DATE, 'DD-MON-YYYY') || 
                             ', Location: ' || accident_rec.LOCATION);
    END LOOP;
END;
/

SQL> execute accident_info('Delhi India');
Report Number: 1, Date: 01-JAN-24, Location: Delhi India

PL/SQL procedure successfully completed.

4. Create a procedure to identify all drivers who have never been involved in any accidents. The procedure should return their driver-id, name, and address.

SQL> 
CREATE OR REPLACE PROCEDURE GetDriversWithoutAccidents AS
BEGIN
    FOR rec IN (
        SELECT p.driver_id#, p.name, p.address
        FROM person p
        LEFT JOIN participated pa ON p.driver_id# = pa.driver_id#
        WHERE pa.report_number IS NULL
    ) LOOP
        DBMS_OUTPUT.PUT_LINE('driver id: ' || rec.driver_id# ||
                             ', name: ' || rec.name ||
                             ', address: ' || rec.address);
    END LOOP;
END;
/

SQL> EXEC GetDriversWithoutAccidents;
Driver ID: 1237, Name: Saarthak, Address: Manipal India
Driver ID: 1235, Name: Rohit, Address: Banglalore India

PL/SQL procedure successfully completed.

Q5. Write a function that takes a REGNO as input and returns the total number of accidents in which the car was involved

SQL> 
CREATE OR REPLACE FUNCTION gettotalaccidentsbyregno(p_regno IN VARCHAR2)
RETURN NUMBER
IS
    v_total_accidents NUMBER := 0; -- Initialize to 0
BEGIN
    SELECT COUNT(*)
    INTO v_total_accidents
    FROM participated
    WHERE REGNO = p_regno;

    RETURN v_total_accidents;
EXCEPTION
    WHEN OTHERS THEN
        RETURN 0; -- Return 0 for any error
END;
/

SQL> SELECT GetTotalAccidentsByRegno('ABCD0001') AS Total_Accidents
    FROM dual;

TOTAL_ACCIDENTS
---------------
              1

SQL> SELECT c.REGNO, GetTotalAccidentsByRegno(c.REGNO) AS Total_Accidents
    FROM car c;

REGNO                TOTAL_ACCIDENTS
-------------------- ---------------
ABCD0001                           1
ABCD4001                           0
DSDS0001                           1
EFGH2001                           0
HFSP5601                           2