59 lines
1.5 KiB
Markdown
59 lines
1.5 KiB
Markdown
|
# P3 - Cursor
|
||
|
|
|
||
|
|
**Problem Statement:** Write a PL/SQL block of code using Cursor that will merge the data available in the newly created table N_Roll Call with the data available in the table O_RollCall. If the data in the first table already exist in the second table, then that data should be skipped.
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
## Creating tables
|
||
|
|
```plsql
|
||
|
|
CREATE TABLE O_RollCall (
|
||
|
|
roll NUMBER NOT NULL,
|
||
|
|
name VARCHAR2(255),
|
||
|
|
class VARCHAR2(255)
|
||
|
|
);
|
||
|
|
|
||
|
|
CREATE TABLE N_RollCall (
|
||
|
|
roll NUMBER NOT NULL,
|
||
|
|
name VARCHAR2(255),
|
||
|
|
class VARCHAR2(255)
|
||
|
|
);
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
## Inserting values
|
||
|
|
```plsql
|
||
|
|
INSERT INTO O_RollCall VALUES (2, 'Eddie', 'COMP-2');
|
||
|
|
INSERT INTO O_RollCall VALUES (3, 'Foxy', 'COMP-1');
|
||
|
|
INSERT INTO O_RollCall VALUES (5, 'Stomp', 'COMP-3');
|
||
|
|
|
||
|
|
INSERT INTO N_RollCall VALUES (1, 'Stewie', 'COMP-1');
|
||
|
|
INSERT INTO N_RollCall VALUES (2, 'Eddie', 'COMP-2');
|
||
|
|
INSERT INTO N_RollCall VALUES (3, 'Foxy', 'COMP-1');
|
||
|
|
INSERT INTO N_RollCall VALUES (4, 'Lara', 'COMP-3');
|
||
|
|
INSERT INTO N_RollCall VALUES (5, 'Stomp', 'COMP-3');
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
## Procedure
|
||
|
|
```plsql
|
||
|
|
DECLARE
|
||
|
|
p_roll NUMBER;
|
||
|
|
p_name VARCHAR2(255);
|
||
|
|
p_class VARCHAR2(255);
|
||
|
|
CURSOR c1 IS SELECT * FROM N_RollCall WHERE roll NOT IN (SELECT roll FROM O_RollCall);
|
||
|
|
BEGIN
|
||
|
|
OPEN c1;
|
||
|
|
LOOP
|
||
|
|
FETCH c1 INTO p_roll, p_name, p_class;
|
||
|
|
INSERT INTO O_RollCall VALUES (p_roll, p_name, p_class);
|
||
|
|
EXIT WHEN c1%NOTFOUND;
|
||
|
|
DBMS_OUTPUT.PUT_LINE('Inserted ' || p_name || ' having roll no. ' || p_roll || ' in class ' || p_class || '.');
|
||
|
|
END LOOP;
|
||
|
|
CLOSE c1;
|
||
|
|
END;
|
||
|
|
/
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
---
|