59 lines
1.5 KiB
Markdown
59 lines
1.5 KiB
Markdown
# P3 - Cursor
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**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.
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---
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## Creating tables
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```plsql
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CREATE TABLE O_RollCall (
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roll NUMBER NOT NULL,
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name VARCHAR2(255),
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class VARCHAR2(255)
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);
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CREATE TABLE N_RollCall (
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roll NUMBER NOT NULL,
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name VARCHAR2(255),
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class VARCHAR2(255)
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);
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```
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## Inserting values
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```plsql
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INSERT INTO O_RollCall VALUES (2, 'Eddie', 'COMP-2');
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INSERT INTO O_RollCall VALUES (3, 'Foxy', 'COMP-1');
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INSERT INTO O_RollCall VALUES (5, 'Stomp', 'COMP-3');
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INSERT INTO N_RollCall VALUES (1, 'Stewie', 'COMP-1');
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INSERT INTO N_RollCall VALUES (2, 'Eddie', 'COMP-2');
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INSERT INTO N_RollCall VALUES (3, 'Foxy', 'COMP-1');
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INSERT INTO N_RollCall VALUES (4, 'Lara', 'COMP-3');
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INSERT INTO N_RollCall VALUES (5, 'Stomp', 'COMP-3');
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```
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## Procedure
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```plsql
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DECLARE
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p_roll NUMBER;
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p_name VARCHAR2(255);
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p_class VARCHAR2(255);
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CURSOR c1 IS SELECT * FROM N_RollCall WHERE roll NOT IN (SELECT roll FROM O_RollCall);
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BEGIN
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OPEN c1;
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LOOP
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FETCH c1 INTO p_roll, p_name, p_class;
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INSERT INTO O_RollCall VALUES (p_roll, p_name, p_class);
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EXIT WHEN c1%NOTFOUND;
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DBMS_OUTPUT.PUT_LINE('Inserted ' || p_name || ' having roll no. ' || p_roll || ' in class ' || p_class || '.');
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END LOOP;
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CLOSE c1;
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END;
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/
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```
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---
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