text: -- Creating tables for PH-EmployeeDB
  CREATE TABLE departments (
       dept_no VARCHAR(4) NOT NULL,
       dept_name VARCHAR(40) NOT NULL,
       PRIMARY KEY (dept_no),
       UNIQUE (dept_name)
  );
  
  CREATE TABLE employees (
  	 emp_no INT NOT NULL,
       birth_date DATE NOT NULL,
       first_name VARCHAR NOT NULL,
       last_name VARCHAR NOT NULL,
       gender VARCHAR NOT NULL,
       hire_date DATE NOT NULL,
       PRIMARY KEY (emp_no)
  );
  
  CREATE TABLE dept_manager (
  dept_no VARCHAR(4) NOT NULL,
      emp_no INT NOT NULL,
      from_date DATE NOT NULL,
      to_date DATE NOT NULL,
  FOREIGN KEY (emp_no) REFERENCES employees (emp_no),
  FOREIGN KEY (dept_no) REFERENCES departments (dept_no),
      PRIMARY KEY (emp_no, dept_no)
  );
  
  CREATE TABLE salaries (
  	emp_no INT NOT NULL,
      salary INT NOT NULL,
      from_date DATE NOT NULL,
      to_date DATE NOT NULL,
      FOREIGN KEY (emp_no) REFERENCES employees (emp_no),
      PRIMARY KEY (emp_no)
  );
  
  CREATE TABLE dept_emp (
  	emp_no INT NOT NULL,
      dept_no VARCHAR(4) NOT NULL,
      from_date DATE NOT NULL,
      to_date DATE NOT NULL,
      FOREIGN KEY (emp_no) REFERENCES employees (emp_no),
      FOREIGN KEY (dept_no) REFERENCES departments (dept_no),
      PRIMARY KEY (emp_no, dept_no)
  );
  
  CREATE TABLE titles (
  	emp_no INT NOT NULL,
      title VARCHAR(40) NOT NULL,
  	from_date DATE NOT NULL,
      to_date DATE NOT NULL,
  	FOREIGN KEY (emp_no) REFERENCES employees (emp_no),
      PRIMARY KEY (emp_no)
  );
  
  SELECT * FROM departments;