The Double-Edged Sword of Dynamic SQL: EXECUTE Anti-Pattern, SQL Injection, Plan Cache Bloat, and Microsoft Defender for SQL
1. Introduction: The Convenience and The Curse of Dynamic SQL In the world of Microsoft SQL Server, dynamic SQL stands as a powerful, double-edged sword. It offers unparalleled flexibility, allowing developers to construct and execute SQL statements whose exact form isn't known until runtime. This capability is invaluable for building highly adaptable applications, supporting complex reporting needs, or implementing advanced administrative tasks where the queries themselves must evolve based on user input or system state. From generating highly customizable search functionalities to building schema-aware migration scripts, dynamic SQL empowers us to overcome the static limitations of traditional T-SQL. However, with great power comes great responsibility. One of the most prevalent and dangerous anti-patterns involving dynamic SQL is the direct use of EXECUTE with string variables that incorporate unchecked or unvalidated user input. While seemingly convenient, this practice opens...