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+---
+name: "database-designer"
+description: "Database Designer - POWERFUL Tier Skill"
+---
+
+# Database Designer - POWERFUL Tier Skill
+
+## Overview
+
+A comprehensive database design skill that provides expert-level analysis, optimization, and migration capabilities for modern database systems. This skill combines theoretical principles with practical tools to help architects and developers create scalable, performant, and maintainable database schemas.
+
+## Core Competencies
+
+### Schema Design & Analysis
+- **Normalization Analysis**: Automated detection of normalization levels (1NF through BCNF)
+- **Denormalization Strategy**: Smart recommendations for performance optimization
+- **Data Type Optimization**: Identification of inappropriate types and size issues
+- **Constraint Analysis**: Missing foreign keys, unique constraints, and null checks
+- **Naming Convention Validation**: Consistent table and column naming patterns
+- **ERD Generation**: Automatic Mermaid diagram creation from DDL
+
+### Index Optimization
+- **Index Gap Analysis**: Identification of missing indexes on foreign keys and query patterns
+- **Composite Index Strategy**: Optimal column ordering for multi-column indexes
+- **Index Redundancy Detection**: Elimination of overlapping and unused indexes
+- **Performance Impact Modeling**: Selectivity estimation and query cost analysis
+- **Index Type Selection**: B-tree, hash, partial, covering, and specialized indexes
+
+### Migration Management
+- **Zero-Downtime Migrations**: Expand-contract pattern implementation
+- **Schema Evolution**: Safe column additions, deletions, and type changes
+- **Data Migration Scripts**: Automated data transformation and validation
+- **Rollback Strategy**: Complete reversal capabilities with validation
+- **Execution Planning**: Ordered migration steps with dependency resolution
+
+## Database Design Principles
+→ See references/database-design-reference.md for details
+
+## Best Practices
+
+### Schema Design
+1. **Use meaningful names**: Clear, consistent naming conventions
+2. **Choose appropriate data types**: Right-sized columns for storage efficiency
+3. **Define proper constraints**: Foreign keys, check constraints, unique indexes
+4. **Consider future growth**: Plan for scale from the beginning
+5. **Document relationships**: Clear foreign key relationships and business rules
+
+### Performance Optimization
+1. **Index strategically**: Cover common query patterns without over-indexing
+2. **Monitor query performance**: Regular analysis of slow queries
+3. **Partition large tables**: Improve query performance and maintenance
+4. **Use appropriate isolation levels**: Balance consistency with performance
+5. **Implement connection pooling**: Efficient resource utilization
+
+### Security Considerations
+1. **Principle of least privilege**: Grant minimal necessary permissions
+2. **Encrypt sensitive data**: At rest and in transit
+3. **Audit access patterns**: Monitor and log database access
+4. **Validate inputs**: Prevent SQL injection attacks
+5. **Regular security updates**: Keep database software current
+
+## Conclusion
+
+Effective database design requires balancing multiple competing concerns: performance, scalability, maintainability, and business requirements. This skill provides the tools and knowledge to make informed decisions throughout the database lifecycle, from initial schema design through production optimization and evolution.
+
+The included tools automate common analysis and optimization tasks, while the comprehensive guides provide the theoretical foundation for making sound architectural decisions. Whether building a new system or optimizing an existing one, these resources provide expert-level guidance for creating robust, scalable database solutions.