Everything I write in class demo will appear here step by step. You just need to keep this page open and update it from time to time

/* First change the editor */
define _editor=nano
/* To see what tables you already have */
select table_name from user_tables;
/* Create a table with two attributes and no primary key */
CREATE TABLE test_table
(a INTEGER, b VARCHAR2(10));
/* Drop table */
DROP TABLE test_table;
/* Drop table */
DROP TABLE test_table;
/* Create table with primary key */
CREATE TABLE people
(id INTEGER,
name VARCHAR2(10),
PRIMARY KEY (id));
/* See description of the table */
desc people;

/* Insert 2 tuples in the table */
INSERT INTO people VALUES (1, 'vladimir');
INSERT INTO people(name, id) VALUES ('evgeny', 2);

/* List all data from the tables */
SELECT * FROM people;

/* List all data from the tables */
SELECT * FROM people;
/* Change some data in the table */
UPDATE peopleupda
SET id = 3
WHERE name= 'evgeny';

/* List all data from the table */
SELECT * FROM people;
/* Delete some data from the table */
DELETE FROM people
WHERE id=3;

/* Add one more table at the beginning of the file */
CREATE TABLE album(
id CHAR(10) NOT NULL PRIMARY KEY,
title VARCHAR(100),
artist VARCHAR(100)
); /* Add foregn key in the track table*/
CREATE TABLE track(
ed album CHAR(10),
ed disk INTEGER,
posn INTEGER,
song VARCHAR(255),
PRIMARY KEY (album, disk, posn),
FOREIGN KEY (album) REFERENCES album
);

/* Now add insert statements at the end of the file */
insert into album values(1,'title','artist');
insert into track values(1,1,1,'song');
/* Altering tables, we don't need editor any more*/
CREATE TABLE a(x INTEGER, y INTEGER);
INSERT INTO a VALUES (1,2);
ALTER TABLE a ADD z INTEGER;
SELECT * FROM a;
ALTER TABLE a DROP COLUMN z;