Moved old Queries-A6 to Queries-A7 since it's the cursor assignment.

Practical/Assignment-A7/Queries-A7.md

@@ -1,91 +1,110 @@
+# Database Queries for Assignment-A7
+
 ## Creating tables
 
-`Library` table:
+`O_RollCall` table:
 ```sql
-CREATE TABLE Library(
+CREATE TABLE O_RollCall(
-    id NUMBER(12),
+name VARCHAR(255),
-    title VARCHAR(255),
+roll NUMBER(14),
-    dateofissue DATE,
+class VARCHAR(255)
-    author VARCHAR(255)
 );
 
 ```
 
-`Library_Audit` table:
+`N_RollCall` table:
 ```sql
-CREATE TABLE Library_Audit(
+CREATE TABLE N_RollCall(
-    id NUMBER(12),
+name VARCHAR(255),
-    title VARCHAR(255),
+roll NUMBER(14),
-    dateofaction DATE,
+class VARCHAR(255)
-    author VARCHAR(255),
-    status VARCHAR(255)
 );
 
 ```
 
-## Inserting values
+## Inserting data
 
-`Library` table:
+`O_RollCall` table:
 ```sql
-INSERT INTO Library VALUES (1, 'Berserk', TO_DATE('2024-07-28','YYYY-MM-DD'), 'Prashant');
+INSERT INTO O_RollCall VALUES ('Stewie', 1, 'Comp 1');
-INSERT INTO Library VALUES (2, 'Dark', TO_DATE('2024-07-15','YYYY-MM-DD'), 'Rajendra');
+INSERT INTO O_RollCall VALUES ('Edie', 2, 'Comp 2');
-INSERT INTO Library VALUES (3, 'Hannibal', TO_DATE('2024-07-20','YYYY-MM-DD'), 'Manoj');
+INSERT INTO O_RollCall VALUES ('Stomp', 3, 'Comp 3');
-INSERT INTO Library VALUES (4, 'AOT', TO_DATE('2024-07-30','YYYY-MM-DD'), 'Rajesh');
+INSERT INTO O_RollCall VALUES ('Lara', 4, 'Comp 1');
-INSERT INTO Library VALUES (5, 'GOT', TO_DATE('2024-07-19','YYYY-MM-DD'), 'Anil');
+INSERT INTO O_RollCall VALUES ('Foxy', 5, 'Comp 2');
 
 ```
 
-## Trigger
+`N_RollCall` table:
-
 ```sql
-CREATE OR REPLACE TRIGGER library_action
+INSERT INTO N_RollCall VALUES ('Stewie', 1, 'Comp 1');
-AFTER INSERT OR UPDATE OR DELETE ON Library
+INSERT INTO N_RollCall VALUES ('Edie', 2, 'Comp 2');
-FOR EACH ROW
+INSERT INTO N_RollCall VALUES ('Stomp', 3, 'Comp 3');
+INSERT INTO N_RollCall VALUES ('Lara', 4, 'Comp 1');
+INSERT INTO N_RollCall VALUES ('Foxy', 5, 'Comp 2');
+INSERT INTO N_RollCall VALUES ('Gundeti', 6, 'Comp 3');
+INSERT INTO N_RollCall VALUES ('Kalas', 7, 'Comp 2');
+
+```
+
+## Procedure
+
+### Explicit cursor
+```sql
+DECLARE
+  p_name VARCHAR(255);
+  p_rollno NUMBER(15);
+  p_class VARCHAR(255);
+  CURSOR cc1 IS SELECT * FROM N_RollCall WHERE roll NOT IN (SELECT roll FROM O_RollCall);
 BEGIN
-	IF INSERTING THEN
+  OPEN cc1;
-    	INSERT INTO Library_Audit (id, title, dateofaction, author, status) VALUES (:NEW.id, :NEW.title, current_timestamp, :NEW.author, 'Insert');
+    LOOP
-	ELSIF UPDATING THEN
+      FETCH cc1 INTO p_name, p_rollno, p_class;
-        INSERT INTO Library_Audit (id, title, dateofaction, author, status) VALUES (:OLD.id, :OLD.title, current_timestamp, :OLD.author, 'Update');
+      INSERT INTO O_RollCall VALUES (p_name, p_rollno, p_class);
-	ELSIF DELETING THEN
+      EXIT WHEN cc1%notfound;
-        INSERT INTO Library_Audit (id, title, dateofaction, author, status) VALUES (:OLD.id, :OLD.title, current_timestamp, :OLD.author, 'Delete');
+      DBMS_OUTPUT.PUT_LINE(p_name || ' ' || p_rollno || ' ' || p_class);
-	END IF;
+      END LOOP;
+  CLOSE cc1;
 END;
 /
 
 ```
 
-## Testing trigger
+### Parameterized cursor
-
-### Insert operation
-
 ```sql
-INSERT INTO Library VALUES (15, 'CREW', TO_DATE('2024-07-22','YYYY-MM-DD'), 'Ramesh');
+DECLARE
-INSERT INTO Library VALUES (14, 'Ninteen Eighty Four', TO_DATE('2024-07-01','YYYY-MM-DD'), 'Omkar');
+  p_name VARCHAR(255);
+  p_rollno NUMBER(15);
+  p_class VARCHAR(255);
+  CURSOR pp1(roll1 NUMBER) IS SELECT * FROM N_RollCall WHERE roll > roll1;
 
-SELECT * FROM Library;
+BEGIN
-SELECT * FROM Library_Audit;
+  OPEN pp1(3);
+    LOOP
+      FETCH pp1 INTO p_name, p_rollno, p_class;
+      EXIT WHEN pp1%notfound;
+      DBMS_OUTPUT.PUT_LINE(p_name || ' ' || p_rollno || ' ' || p_class);
+    END LOOP;
+  CLOSE pp1;
 
-```
+END;
-### Update operation
+/
-
-```sql
-UPDATE Library SET id = 6, title = 'Sherlock', author = 'Deepak' where id = 3;
-UPDATE Library SET id = 7, title = 'MR. ROBOT', author = 'Varad' where id = 4;
-
-SELECT * FROM Library;
-SELECT * FROM Library_Audit;
 
 ```
 
-### Delete operation
+### Implicit Cursor
-
 ```sql
-DELETE FROM Library WHERE id = 1;
+DECLARE
-DELETE FROM Library WHERE id = 5;
+  total_rows NUMBER(2);
 
-SELECT * FROM Library;
+BEGIN
-SELECT * FROM Library_Audit;
+  UPDATE N_RollCall SET roll = roll + 1;
+  IF sql%notfound THEN
+    dbms_output.put_line('no roll was updated');
+  ELSIF sql%found THEN
+    total_rows := sql%rowcount;
+    DBMS_OUTPUT.PUT_LINE( total_rows || ' roll calls were affected ');
+  END IF;
+END;
+/
 
 ```
-
----