2nd/10_Wiki/Dev/Topic_SQL/SQL_Parameters.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
sql-parameters	SQL Parameters	Database	draft	conceptual		Parameterized Queries SQL 파라미터화 쿼리		B	0.87	2026-07-04	2026-07-04			sql database w3schools security parameters	https://www.w3schools.com/sql/sql_parameterized_queries.asp

SQL Parameters

🎯 한 줄 통찰 (One-line insight)

Parameterized queries fix SQL injection by sending user input as placeholder-bound values instead of concatenated text, so the database always treats the input literally, never as executable SQL. [S1]

🧠 핵심 개념 (Core concepts)

• Parameterized query — an SQL statement using placeholders instead of directly embedding input values in the query text; placeholders are replaced with actual values at execution time. [S1]
• Placeholder syntax varies by vendor — MySQL uses ?, SQL Server uses @, PostgreSQL uses $. [S1]
• Literal treatment guarantee — the SQL engine checks each parameter against its column type and treats it literally, not as part of the executable SQL — this is what neutralizes injection. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Same fix for SELECT and INSERT — the parameterization pattern applies identically whether reading (SELECT ... WHERE UserId = @userid) or writing (INSERT INTO ... VALUES(@cname, @caddress, @ccity)). [S1]
• Bind-then-execute in application code — frameworks like ASP.NET separate building the query text (with placeholders) from binding actual values (cmd.Parameters.AddWithValue(...)), directly countering the string-concatenation root cause from SQL Injection. [S1]

📖 세부 내용 (Details)

• SQL Server-style placeholder query: query = "SELECT * FROM Users WHERE UserId = @userid"; db.Execute(query, userid);. [S1]
• Parameterized INSERT: query = "INSERT INTO Customers (CustomerName, Address, City) Values(@cname, @caddress, @ccity)"; db.Execute(query, cname, caddress, ccity);. [S1]
• ASP.NET binding pattern: cmd = new SqlCommand(query); cmd.Parameters.AddWithValue("@userid", userid); cmd.ExecuteReader();. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 앞서 SQL Injection 챕터에서 보여준 문자열 연결(concatenation) 취약점을 직접 해소하는 대응책이다. [S1]

💻 코드 패턴 (Code patterns)

Parameterized SELECT (ASP.NET, SQL Server style):

userid = getRequestString("UserId");
query = "SELECT * FROM Customers WHERE CustomerId = @userid";
cmd = new SqlCommand(query);
cmd.Parameters.AddWithValue("@userid", userid);
cmd.ExecuteReader();

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.87
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: SQL Tutorial
• 관련 개념: SQL Injection, SQL Prepared Statements
• 참조 맥락: SQL Injection의 직접적인 대응책 — Prepared Statements와 함께 사용자 입력을 다루는 표준 방어법.

📚 출처 (Sources)

• [S1] W3Schools — SQL Parameters — https://www.w3schools.com/sql/sql_parameterized_queries.asp

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "SQL Parameters" page (Astra wiki-curation, P-Reinforce v3.1 format).