CREATE TABLE IF NOT EXISTS orders
(
    id         BIGSERIAL PRIMARY KEY,
    user_id    BIGINT REFERENCES users (id) NOT NULL,
    created_at DATE                         NOT NULL
);
CREATE TABLE IF NOT EXISTS order_entries
(
    product_id       BIGINT REFERENCES products (id) NOT NULL,
    order_id         BIGINT REFERENCES orders (id)   NOT NULL,
    product_quantity BIGINT                          NOT NULL,
    price            NUMERIC(15, 2)                  NOT NULL,
    total            NUMERIC(15, 2)                  NOT NULL
);
CREATE TABLE IF NOT EXISTS carts
(
    id               BIGSERIAL PRIMARY KEY,
    product_id       BIGINT REFERENCES products (id) NOT NULL,
    product_quantity BIGINT                          NOT NULL,
    user_id          BIGINT REFERENCES users (id)    NOT NULL
);