Simplified and improved queries for A6.

- Separate sections for creating tables and inserting data
- Fixed IF control block in procedure
- Refined procedure and calling block

Practical/Assignment-A6/Queries-A6.md

@@ -1,78 +1,79 @@
 # Database Queries for Assignment-A6
 
-## Creating tables & inserting data
+## Creating tables
 
-Student marks:
 ```sql
-CREATE TABLE Stud_Marks(
-    Roll NUMBER(14),
-    name VARCHAR(255),
-    total_marks NUMBER(14),
-    PRIMARY KEY(Roll)
-
+CREATE TABLE Stud_Marks (
+  roll INT,
+  name VARCHAR(255),
+  total_marks INT,
+  PRIMARY KEY (roll)
 );
 
-INSERT INTO Stud_Marks VALUES (1, 'Arora', 1350);
-INSERT INTO Stud_Marks VALUES (2, 'Shankar', 979);
-INSERT INTO Stud_Marks VALUES (3, 'Lara', 834);
-INSERT INTO Stud_Marks VALUES (4, 'Jambo', 667);
-INSERT INTO Stud_Marks VALUES (5, 'Tinde', 1400);
+CREATE TABLE Result (
+  roll INT,
+  name VARCHAR(255),
+  class VARCHAR(255),
+  FOREIGN KEY (roll) REFERENCES Stud_Marks (roll)
+);
 
 ```
 
-Result:
+## Inserting data
+
 ```sql
-CREATE TABLE Result(
-    Roll NUMBER(14),
-    name VARCHAR(255),
-    Class VARCHAR(255),
-    FOREIGN KEY (Roll) REFERENCES Stud_Marks (Roll)
-);
+INSERT INTO Stud_Marks VALUES (1, 'Kshitij', 1400);
+INSERT INTO Stud_Marks VALUES (2, 'Kalas', 500);
+INSERT INTO Stud_Marks VALUES (3, 'Himanshu', 995);
+INSERT INTO Stud_Marks VALUES (4, 'MEPA', 850);
+INSERT INTO Stud_Marks VALUES (5, 'Macho', 900);
 
 ```
 
 ## Procedure
+
 ```sql
-CREATE OR REPLACE PROCEDURE proc_grade
-(rollno in number,
- p_roll_no out Stud_Marks.Roll%type,
- p_name out Stud_Marks.name%type,
- p_total out Stud_Marks.total_marks%type)
-AS
+CREATE OR REPLACE PROCEDURE proc_Grade (roll_no IN NUMBER) AS
+
+-- declare section
+  p_roll Stud_Marks.roll%TYPE;
+  p_name Stud_Marks.name%TYPE;
+  p_total NUMBER;
+
 BEGIN
-	SELECT Roll, name, total_marks into p_roll_no, p_name, p_total from Stud_Marks WHERE Roll = rollno;
-	IF p_total <= 1500 and p_total >= 990
-	THEN
-		INSERT INTO Result VALUES (p_roll_no, p_name, 'Distinction');
-	ELSE IF p_total <= 989 and p_total >= 900
-	THEN
-		INSERT INTO Result VALUES (p_roll_no, p_name, 'First Class');
-	ELSE IF p_total <= 899 and p_total >= 825
-	THEN
-		INSERT INTO Result VALUES (p_roll_no, p_name, 'Higher Second Class');
-	ELSE
-		INSERT INTO Result VALUES (p_roll_no, p_name, 'FAIL');
-	END IF;
-	END IF;
-	END IF;
+  SELECT roll, name, total_marks INTO p_roll, p_name, p_total FROM Stud_Marks WHERE roll = roll_no;
+
+  IF (p_total <= 1500 AND p_total >= 990) THEN
+    INSERT INTO Result VALUES (p_roll, p_name, 'Distinction');
+    DBMS_OUTPUT.PUT_LINE(p_name || ' (roll no. ' || p_roll || ') has been placed in the DISTINCTION category.');
+  ELSIF (p_total BETWEEN 900 AND 989) THEN
+    INSERT INTO Result VALUES (p_roll, p_name, 'First Class');
+    DBMS_OUTPUT.PUT_LINE(p_name || ' (roll no. ' || p_roll || ') has been placed in the FIRST CLASS.');
+  ELSIF (p_total BETWEEN 825 AND 899) THEN
+    INSERT INTO Result VALUES (p_roll, p_name, 'Higher Second Class');
+    DBMS_OUTPUT.PUT_LINE(p_name || ' (roll no. ' || p_roll || ') has been placed in the HIGHER SECOND CLASS.');
+  ELSE
+    INSERT INTO Result VALUES (p_roll, p_name, 'Fail');
+    DBMS_OUTPUT.PUT_LINE(p_name || ' (roll no. ' || p_roll || ') has FAILED.');
+  END IF;
+
 EXCEPTION
-	WHEN no_data_found THEN
-		dbms_output.put_line('Rollno ' || rollno || ' is not present!!');
-END;
+  WHEN NO_DATA_FOUND THEN
+    DBMS_OUTPUT.PUT_LINE('No entry for this roll number in the Stud_Marks database.');
+
+END proc_Grade;
 /
 
 ```
 
-## Calling Procedure:
+## Calling procedure
+
 ```sql
 DECLARE
-	rollno number(14);
-	p_roll_no Stud_Marks.Roll%type;
-	p_name Stud_Marks.name%type;
-	p_total_marks Stud_Marks.total_marks%type;
+  roll_no NUMBER;
 BEGIN
-	rollno := &rollno;
-	proc_grade(rollno, p_roll_no, p_name, p_total_marks);
+  roll_no := &roll_no; -- replace &roll_no with a number for Live SQL since it does not support user input.
+  proc_Grade(roll_no);
 END;
 /