CREATE TABLE dsolovianov.users (
    id			INT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    name		VARCHAR(100) NOT NULL,
    age			INT,
    email		VARCHAR(100),
    country		VARCHAR(100),
    is_active	BOOLEAN,
    created_at	TIMESTAMPTZ NOT NULL
);

CREATE TABLE dsolovianov.products (
	id			INT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
	name		VARCHAR(100) NOT NULL,
	category	VARCHAR(50),
	price		DECIMAL(10,2) NOT NULL,
	in_stock	BOOLEAN
	);

CREATE TABLE dsolovianov.orders (
    id			INT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    user_id		INT,
    order_date  TIMESTAMPTZ NOT NULL,
    status		VARCHAR(20)
);

CREATE TABLE dsolovianov.order_items (
    order_id           INT NOT NULL,
    product_id         INT NOT NULL,
    quantity           INT NOT NULL CHECK (quantity > 0),
    price_at_purchase  DECIMAL(10,2) NOT NULL CHECK (price_at_purchase > 0),
    CONSTRAINT order_items_pk PRIMARY KEY (order_id, product_id)
    CONSTRAINT order_items_order_fk
    	FOREIGN KEY (order_id) REFERENCES dsolovianov.orders(id),
    CONSTRAINT order_items_product_fk
    	FOREIGN KEY (product_id) REFERENCES dsolovianov.products(id),
    CONSTRAINT orders_user_fk
    	FOREIGN KEY (user_id) REFERENCES dsolovianov.users(id)
);