docs(10_Wiki): Topic_Business/General/Graphic/Programming을 Topics/ 하위로 이동

최상위 10_Wiki/Topic_*였던 4개 카테고리 폴더를 10_Wiki/Topics/Topic_* 로 재배치. 콘텐츠 변경 없음(순수 폴더 이동) — Topics/ 하위 나머지 폴더는 이미 지난 커밋에서 전부 정리된 상태(잔존 항목은 에이전트 운영 상태 및 사용자가 보존을 요청한 업데이트0615/무제 3.canvas 뿐).
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+---
+id: sql-check
+title: "SQL Check"
+category: "Database"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["SQL CHECK Constraint", "CHECK constraint"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.9
+created_at: 2026-07-04
+updated_at: 2026-07-04
+review_reason: ""
+merge_history: []
+tags: ["sql", "database", "w3schools", "check", "constraints"]
+raw_sources: ["https://www.w3schools.com/sql/sql_check.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[SQL Check]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+CHECK enforces an arbitrary boolean condition on a column (or combination of columns) — an INSERT/UPDATE that would evaluate the condition to FALSE is aborted entirely. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **CHECK constraint** — ensures values in a column satisfy a specific condition; evaluates to TRUE or FALSE, and FALSE aborts the entire INSERT/UPDATE with an error. [S1]
+- **On CREATE TABLE** — inline, e.g. `Age int CHECK (Age >= 18)`. [S1]
+- **Named, multi-column CHECK** — `CONSTRAINT chk_PersonAge CHECK (Age >= 18 AND City = 'Sandnes')` combines multiple column conditions under one name. [S1]
+- **On ALTER TABLE** — `ALTER TABLE Persons ADD CHECK (Age >= 18);` or the named/multi-column form via `ADD CONSTRAINT`. [S1]
+- **Dropping** — `DROP CONSTRAINT chk_PersonAge;` (SQL Server/Oracle/Access) vs. `DROP CHECK chk_PersonAge;` (MySQL). [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+- **드롭 문법 차이**: SQL Server/Oracle/Access는 `DROP CONSTRAINT`, MySQL은 `DROP CHECK`를 사용. [S1]
+
+## 📖 세부 내용 (Details)
+- Single-column CHECK: `CREATE TABLE Persons (ID int PRIMARY KEY, LastName varchar(255) NOT NULL, FirstName varchar(255), Age int CHECK (Age >= 18));`. [S1]
+- Named, multi-column CHECK: `CONSTRAINT chk_PersonAge CHECK (Age >= 18 AND City = 'Sandnes')`. [S1]
+- Add to existing table: `ALTER TABLE Persons ADD CHECK (Age >= 18);`. [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — DEFAULT/NOT NULL만으로 표현할 수 없는 임의 비즈니스 규칙(나이 제한, 값 범위)을 강제할 때 쓰인다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+Named CHECK across two columns (SQL):
+```sql
+CREATE TABLE Persons (
+    ID int PRIMARY KEY,
+    LastName varchar(255) NOT NULL,
+    FirstName varchar(255),
+    Age int,
+    City varchar(255),
+    CONSTRAINT chk_PersonAge CHECK (Age >= 18 AND City = 'Sandnes')
+);
+```
+
+## ✅ 검증 상태 및 신뢰도
+- **상태:** draft
+- **검증 단계:** conceptual
+- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
+- **신뢰 점수:** 0.90
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[SQL Tutorial]]
+- **관련 개념:** [[SQL Constraints]], [[SQL Default]], [[SQL Not Null]]
+- **참조 맥락:** 임의의 비즈니스 규칙을 컬럼 값에 강제할 때 사용.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — SQL CHECK Constraint — https://www.w3schools.com/sql/sql_check.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "SQL CHECK Constraint" page (Astra wiki-curation, P-Reinforce v3.1 format).