SQL

The language for querying relational databases; injection abuses it.

Structured Query Language is the standard language for defining and querying relational databases, used to read, insert, update, and delete records. Its security relevance comes from injection, where attacker controlled input is concatenated into queries and executed, enabling data theft, authentication bypass, or full database compromise. The primary defense is parameterized queries or prepared statements, supported by least privilege accounts and input validation. On the exam, link SQL directly to SQLi and to the input handling failures that allow it.