MySQL Database Design and Query Optimization
Design relational schemas, write complex queries, and optimize database performance.
About This Assessment
SQL and relational database skills remain foundational across virtually all backend roles, with data analysis and database administration among the top 10 in-demand positions. Employers struggle with candidates who claim SQL expertise but cannot write joins, optimize queries, or design normalized schemas. This assessment validates practical database competency in a market where every backend and data role requires SQL proficiency.
What Candidates Will Do
Design a relational database schema with proper normalization (3NF) for a given business scenario (e.g., e-commerce, library system)
Write complex SQL queries including JOINs, subqueries, aggregations (GROUP BY, HAVING), and window functions
Optimize slow queries using indexes, EXPLAIN plans, and query rewriting techniques
Implement a stored procedure or trigger for business logic (e.g., auto-update inventory on order)
Write transactions with proper isolation and rollback handling
Automated Grading
Verify database schema created with correct tables, columns, data types, primary/foreign keys, and constraints; SQL queries return expected result sets with correct row counts; indexes created on appropriate columns; query execution time improves after optimization; stored procedure executes and produces side effects; transactions maintain data integrity (rollback on error); queries follow best practices (no SELECT *, parameterized inputs)
Environment
Ubuntu 22.04 VM with MySQL 8.0 or MariaDB 10.11, mysql client, sample datasets pre-loaded (optional), slow query log enabled for performance tasks
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$49.00