DatabaseManagementSystems/Practical/Practical Exam/PL-SQL/P4 - PL-SQL Block.md

P4 - PL/SQL block

Problem Statement: Write a PL/SQL block for following requirements and handle the exceptions. Roll no. of students will be entered by the user. Attendance of roll no. entered by user will be checked in the Stud table. If attendance is less than 75% then display the message “Term not granted” and set the status in stud table as “Detained”. Otherwise display message “Term granted” and set the status in stud table as “Not Detained”. Student (Roll, Name, Attendance, Status)

---

Creating table

CREATE TABLE Student(
    Roll NUMBER(14),
    Name VARCHAR(255),
    Attendance NUMBER(14),
    Status VARCHAR(255)
);

Inserting data

INSERT INTO Student VALUES (1, 'Tanmay', 76, NULL);
INSERT INTO Student VALUES (2, 'Rajesh', 80, NULL);
INSERT INTO Student VALUES (3, 'Tejas', 88, NULL);
INSERT INTO Student VALUES (4, 'Machkar', 35, NULL);
INSERT INTO Student VALUES (5, 'Jayashree', 74, NULL);

Procedure

DECLARE
    p_att Student.Attendance%type;
    p_roll Student.Roll%type;
    nodata EXCEPTION;
BEGIN
		DBMS_OUTPUT.PUT_LINE('Enter roll number: ');
    p_roll := &p_roll;

    IF (p_roll < 0) THEN
        raise nodata;
    END IF;

    SELECT Attendance INTO p_att FROM Student WHERE Roll = p_roll;

    IF (p_att < 75) THEN
        DBMS_OUTPUT.PUT_LINE('Term not granted to roll no. ' || p_roll);
        UPDATE Student SET Status = 'Detained' WHERE Roll = p_roll;
    ELSIF (p_att >= 75) THEN
        DBMS_OUTPUT.PUT_LINE('Term granted to roll no. ' || p_roll);
        UPDATE Student SET Status = 'Not Detained' WHERE Roll = p_roll;
    END IF;
EXCEPTION
    WHEN nodata THEN
        DBMS_OUTPUT.PUT_LINE('Please enter a valid roll number.');
		WHEN OTHERS THEN
	      DBMS_OUTPUT.PUT_LINE('Error occured. Error: ' || SQLERRM);
END;
/

Output

After entering every Roll no: ROLL NAME ATTENDANCE STATUS
1 Tanmay 76 Not Detained
2 Rajesh 80 Not Detained
3 Tejas 88 Not Detained
4 Machkar 35 Detained
5 Jayashree 74 Detained

---