graph TD
 %% 노드 정의
 subgraph Client
 UserRequest[사용자 요청]
 end
 subgraph "Command Service (쓰기/수정 책임)"
 direction LR
 A[API Controller]
 B(Business Logic)
 C{JPA & Outbox}
 D[MySQL]
 E[Outbox Table]
 end
 subgraph "Query Service (조회 책임)"
 direction LR
 G[Kafka Consumer]
 H[Data Projection]
 I[Redis]
 end
 F[Message Queue - Kafka]
 %% 화살표 연결
 UserRequest -- "CUD Request" --> A
 A --> B
 B -- "@Transactional" --> C
 C --> D
 C --> E
 E -- "Kafka Connect / Scheduler" --> F
 F --> G
 G --> H
 H --> I
 UserRequest -- "Read Request" --> A
 A -- "1. Read from Cache" --> I
 A -- "2. Cache-Miss 시 Fallback" --> B

erDiagram
 USER {
 bigint id PK "유저 ID"
 string username
 string password
 string email
 string nickname
 Role role
 }
 POST {
 bigint id PK "게시글 ID"
 bigint user_id FK
 string title
 text content
 string writer
 int view
 }
 COMMENT {
 bigint id PK "댓글 ID"
 bigint post_id FK
 bigint user_id FK
 text comments
 }
 POST_LIKE {
 bigint id PK "좋아요 ID"
 bigint post_id FK
 bigint user_id FK
 }
 LIKE_COUNT {
 bigint id PK "게시글 ID와 동일"
 long likeCount
 long version "낙관적 락을 위한 버전"
 }
 USER ||--o{ POST : "작성"
 USER ||--o{ COMMENT : "작성"
 USER ||--o{ POST_LIKE : "클릭"
 POST ||--o{ COMMENT : "포함"
 POST ||--o{ POST_LIKE : "포함"
 POST ||--|{ LIKE_COUNT : "가짐"