Entity: Cart

Represents a visitor's shopping cart, identified by a client-generated UUID session ID. No authentication required.

Fields

Field	Type	Nullable	Default	Description
id	serial	no	auto	Primary key
session_id	varchar(36)	no	—	Client-generated UUID identifying the browser session
status	enum(open, closed)	no	open	Cart status — closed after checkout
closed_at	timestamp with time zone	yes	null	Moment the cart was checked out

Standard columns (created_at, updated_at, deleted_at) are inherited per ADR-007 and should not be listed here.

Relations

Relation	Type	Target entity	FK	On delete
items	one-to-many	CartItem	cart_item.cart_id	cascade

Business rules

• Each session_id can have at most one cart with status open at a time.
• A new cart is created automatically when the first item is added for a given session_id.
• Checkout transitions the cart status from open to closed and sets closed_at to the current timestamp.

Notes

• The session_id is a UUID generated and persisted by the client (e.g. in localStorage). The API never generates it.
• Closed carts are kept for history; they are never deleted.