SQL vs NoSQL for system design

Short answer

SQL databases offer ACID transactions and structured schemas; NoSQL databases offer horizontal scaling and flexible schemas. Choose SQL for complex queries and strong consistency, NoSQL for high write throughput and unstructured data. For caching layers, see how caching improves system performance. For distributed principles, see what is the cap theorem and why does it matter.

Steps

1. Analyze your data structure and query patterns
2. Choose SQL if you need joins, transactions, and strict schemas
3. Choose NoSQL if you need massive scale, flexible schemas, or simple key lookups
4. Plan for indexing and sharding strategy
5. Consider polyglot persistence for large systems

Tips

• Many systems use both SQL and NoSQL for different services
• Evaluate managed database services to reduce operational load
• For delivery optimization, see how cdns speed up content delivery