DATABASES GUIDE
MongoDB Interview Questions and Modeling Tips
By the HireReadyAI team · 8 min read
Document modeling, indexes, and when multi-document transactions are worth the cost.
Document modeling
Model for access patterns. Embed when data is read together and bounded; reference when unbounded or shared. Bad embedding creates huge documents and painful updates.
Indexing
Index fields used in filters and sorts. Compound index order matters. Use explain() plans. TTL indexes help session-like data.
Consistency and transactions
Multi-document transactions exist but have costs. Many designs prefer single-document atomicity. Know replica set read preferences and what “eventual” means for your product.