MySQL 8.0

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CREATE TABLE department(
id INTEGER NOT NULL auto_increment,
name VARCHAR(30),
PRIMARY KEY(id)
);
CREATE TABLE roles(
id INTEGER NOT NULL auto_increment,
title VARCHAR(30),
salary DECIMAL,
department_id INTEGER,
PRIMARY KEY(id),
FOREIGN KEY(department_id) REFERENCES department(id)
);

CREATE TABLE employee(
id INTEGER NOT NULL auto_increment,
first_name VARCHAR(30),
last_name VARCHAR(30),
role_id INTEGER,
manager_id INTEGER,
FOREIGN KEY(manager_id) REFERENCES employee(id),
PRIMARY KEY(id),
FOREIGN KEY(role_id) REFERENCES roles(id)
)