Database JSON Column Best Practices

Implement JSON columns for:

Database: [PostgreSQL/MySQL]
Use Case: [DESCRIBE WHAT JSON DATA YOU'RE STORING]
Query Patterns: [HOW YOU'LL QUERY THE JSON]

Requirements:
- Schema validation: [YES/NO]
- Indexing needs: [FIELDS TO INDEX IN JSON]
- Migration from existing: [YES/NO]

Please provide:
1. Column type selection (JSON vs JSONB)
2. Validation constraints
3. GIN/expression index setup
4. Query patterns and syntax
5. Update patterns (partial vs full)
6. When to use vs. normalized tables