What is the difference between cache-aside and write-through caching?

Cache-Aside (Lazy Loading): Application code checks cache first. On miss: fetch from DB, populate cache, return data. On write: update DB, then delete or update cache. Pros: only caches what's actually used; tolerates cache failure (just slower). Cons: cache miss means 3 network calls; possible stale data after update if using SET (prefer DELETE). Write-Through: Every write goes to cache AND DB sy