text: CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
  
  CREATE TABLE company (
    company_id UUID PRIMARY KEY,
    name TEXT NOT NULL
  );
  
  CREATE TABLE department (
    department_id UUID PRIMARY KEY,
    company_id UUID NOT NULL REFERENCES company(company_id),
    name TEXT NOT NULL
  );
  
  CREATE INDEX ON department(company_id);
  
  CREATE TABLE employee (
    employee_id UUID PRIMARY KEY,
    department_id UUID NOT NULL REFERENCES department(department_id),
    name TEXT NOT NULL
  );
  
  CREATE INDEX ON employee(department_id);
  