SQL Injection
An attack where malicious SQL is inserted into a query through user input. Prevented by parameterized queries and prepared statements. Never concatenate user input into SQL.
What is SQL Injection?
An attack where malicious SQL is inserted into a query through user input. Prevented by parameterized queries and prepared statements. Never concatenate user input into SQL.
SQL Injection is a intermediate-level concept that sits in the Security Architecture area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "SQL Injection" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn SQL Injection in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the SQL Injection lessonRelated lessons
Lessons that touch on SQL Injection as part of a larger topic.
Parameterized Queries
The complete defense against SQL injection, separating SQL structure from user data
intermediate · security architecture
Web Application Firewall (WAF)
Filtering malicious HTTP traffic before it reaches your application, blocking SQL injection, XSS, and other web attacks at the edge
intermediate · security architecture
See also
Related glossary terms you might want to look up next.
WAF
Web Application Firewall: filters and monitors HTTP traffic between a web application and the internet. Blocks SQL injection, XSS, and other OWASP top-10 attacks.
XSS
Cross-Site Scripting: an attack where malicious scripts are injected into trusted websites. Prevented by sanitizing user input and setting Content-Security-Policy headers.
SQL
Structured Query Language for managing relational databases. Tables, rows, columns, and powerful joins to query related data.