NoSQL Design Challenges

Introduction

NoSQL design challenges force you out of relational thinking: instead of 3NF tables joined at query time, you design documents shaped like the screens that read them. These exercises walk through five product surfaces and ask the same question for each: what document do I want back?

Understanding the topic

5 surfaces → design exercises:

• 1. Product detail page — variants, reviews summary, related items.
• 2. User dashboard — open tickets, recent activity, KPI widgets.
• 3. Chat thread view — last 50 messages + participants.
• 4. Booking timeline — availability + bookings for a resource.
• 5. Feed page — ranked posts + author info + interaction counts.

Informative example

Surface 1 — product detail page document:

{
  _id, slug, title, brand,
  variants: [ { sku, color, size, priceCents, stock } ],
  media:    [ { assetId, alt, isPrimary } ],
  specs:    { weightG, dimensionsMm, material },
  ratings:  { avg: 4.6, count: 1284 },           // denormalised summary
  recentReviews: [ { id, title, score, snippet } ], // top-3 cached
  related:  [ { productId, title, slug, thumbAssetId } ]
}

Best practices

• Design the document to match the screen — minimise round-trips.
• Denormalise summary stats; recompute on write via aggregation hooks or change streams.
• Embed up to ~50 children, reference beyond.