CREATE TABLE products (
    product_no integer,
    name text,
    price numeric DEFAULT 9.99
);

CREATE TABLE products (
    product_no SERIAL,
    ...
);

CREATE TABLE products (
    product_no integer,
    name text,
    price numeric CONSTRAINT positive_price CHECK (price > 0)
);

CREATE TABLE products (
    product_no integer NOT NULL,
    name text NOT NULL,
    price numeric
);

CREATE TABLE products (
    product_no integer UNIQUE,
    name text,
    price numeric
);

CREATE TABLE example (
    a integer,
    b integer,
    c integer,
    UNIQUE (a, c)
);

CREATE TABLE products (
    product_no integer PRIMARY KEY,
    name text,
    price numeric
);

CREATE TABLE orders (
    order_id integer PRIMARY KEY,
    product_no integer REFERENCES products (product_no),
    quantity integer
);

CREATE TABLE order_items (
    product_no integer REFERENCES products ON DELETE RESTRICT,
    order_id integer REFERENCES orders ON DELETE CASCADE,
    quantity integer,
    PRIMARY KEY (product_no, order_id)
);

CREATE TYPE mood AS ENUM (’sad’, ’ok’, ’happy’);
CREATE TABLE person (
    name text,
    current_mood mood
);

CREATE TABLE sal_emp (
    name text,
    pay_by_quarter integer[],
    schedule text[][]
);

CREATE DATABASE <DB name> OWNER <user>;