E-commerce Order System – Starter

8 min · starter · intro

E-commerce Order System – Starter

Context: Small store. 500 orders/day. Single warehouse.

Starter Design

  • Database: PostgreSQL. Tables: products, inventory, orders, order_items.
  • Flow: Create order → reserve inventory (decrement) → charge payment → confirm. All in one transaction or short sequence.
  • Inventory: Optimistic locking or SELECT FOR UPDATE to prevent oversell.

Why This Works

  • Straightforward to implement
  • Strong consistency for inventory
  • Adequate for single-region, low concurrency

Inline Check 1

How do you prevent overselling inventory in a simple order system?

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