#1

CREATE TABLE IF NOT EXISTS positions (
	id integer PRIMARY KEY,
	title text NOT NULL,
	min_salary numeric
);

#2

INSERT INTO positions (title, min_salary)
VALUES ('DBA', 120000),
       ('Developer', 100000),
       ('Architect', 150000);

#3

SELECT
	id,title,min_salary
FROM
	positions;

#4

CREATE UNIQUE INDEX idx_positions_title ON positions (title);

#5

REPLACE INTO positions (title, min_salary)
VALUES
	('Full Stack Developer', 140000);

#6

SELECT
	id,title,min_salary
FROM
	positions;

#7

REPLACE INTO positions (title, min_salary)
VALUES
	('DBA', 170000);

#8

REPLACE INTO positions (id, min_salary)
VALUES
	(2, 110000);