Normalization vs Denormalization in MySQL

Normalization optimises for clean writes; denormalization optimises for fast reads. Production apps lean normalized, analytics systems often denormalize deliberately — knowing when to do which is a mark of database maturity.

Key Points

• Normalized: no redundancy, consistent updates, more joins per query
• Denormalized: duplicated data, fewer joins, faster reporting reads
• OLTP transaction systems → normalize; OLAP/reporting → denormalize selectively
• Star schemas in analytics are structured denormalization (facts + dimensions)
• Summary tables are a safe denormalization: derived, rebuildable
• Denormalize only with a plan to keep copies in sync (jobs, triggers)