Postgres 12

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CREATE TABLE titles (
    title_id int   NOT NULL,
    title VARCHAR   NOT NULL,
    constraint pk_titles primary key (title_id)
);

-- Employees Table
CREATE TABLE employees (
    emp_no INT   NOT NULL,
    emp_title_id INT   NOT NULL,
    birth_date DATE   NOT NULL,
    first_name VARCHAR   NOT NULL,
    last_name VARCHAR   NOT NULL,
    sex INT   NOT NULL,
    hire_date DATE   NOT NULL,
    CONSTRAINT pk_employees PRIMARY KEY (
        emp_no
     )
);

-- Salaries Table
CREATE TABLE salaries (
    emp_no INT   NOT NULL,
    salary INT   NOT NULL
);

-- Department Manager
CREATE TABLE dept_manager (
    dept_no VARCHAR   NOT NULL,
    emp_no INT   NOT NULL
);

-- Department Numbers
CREATE TABLE departments (
    dept_no VARCHAR   NOT NULL,
    dept_name VARCHAR   NOT NULL,
    CONSTRAINT pk_departments PRIMARY KEY (
        dept_no
     )
);

-- Employee vs. Department
CREATE TABLE dept_emp (
    emp_no INT   NOT NULL,
    dept_no VARCHAR   NOT NULL
);

ALTER TABLE employees ADD CONSTRAINT fk_employees_emp_title_id FOREIGN KEY(emp_title_id)
REFERENCES titles (title_id);

ALTER TABLE salaries ADD CONSTRAINT fk_salaries_emp_no FOREIGN KEY(emp_no)
REFERENCES employees (emp_no);

ALTER TABLE dept_manager ADD CONSTRAINT fk_dept_manager_dept_no FOREIGN KEY(dept_no)
REFERENCES departments (dept_no);

ALTER TABLE dept_manager ADD CONSTRAINT fk_dept_manager_emp_no FOREIGN KEY(emp_no)
REFERENCES employees (emp_no);

ALTER TABLE dept_emp ADD CONSTRAINT fk_dept_emp_emp_no FOREIGN KEY(emp_no)
REFERENCES employees (emp_no);

ALTER TABLE dept_emp ADD CONSTRAINT fk_dept_emp_dept_no FOREIGN KEY(dept_no)
REFERENCES departments (dept_no);

CREATE TABLE

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