Type Mapping Encyclopedia

특수 변환 패턴

-- MySQL ENUM → PostgreSQL
-- 방법 1: CHECK 제약
CREATE TABLE orders (
    status VARCHAR(20) CHECK (status IN ('pending', 'paid', 'shipped'))
);

-- 방법 2: 사용자 정의 타입
CREATE TYPE order_status AS ENUM ('pending', 'paid', 'shipped');
CREATE TABLE orders (status order_status);

-- MySQL AUTO_INCREMENT → PostgreSQL IDENTITY
-- MySQL:
CREATE TABLE users (id INT AUTO_INCREMENT PRIMARY KEY);
-- PostgreSQL:
CREATE TABLE users (id INTEGER GENERATED ALWAYS AS IDENTITY PRIMARY KEY);

-- MySQL ON UPDATE CURRENT_TIMESTAMP → PostgreSQL 트리거
CREATE OR REPLACE FUNCTION update_modified_column()
RETURNS TRIGGER AS $$
BEGIN NEW.updated_at = CURRENT_TIMESTAMP; RETURN NEW; END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER update_timestamp BEFORE UPDATE ON users
FOR EACH ROW EXECUTE FUNCTION update_modified_column();

Oracle → PostgreSQL 매핑

RDBMS → MongoDB 변환 패턴

정규화 해제 전략

관계형:                          문서형:
┌─ users ─┐  ┌─ orders ─┐      {
│ id       │  │ id       │        _id: ObjectId,
│ name     │  │ user_id  │→       name: "홍길동",
│ email    │  │ total    │        email: "[email protected]",
└──────────┘  │ items[]  │        orders: [
              └──────────┘          { total: 50000,
                                      items: [
                                        { product: "A", qty: 2 }
                                      ]
                                    }
                                  ]
                                }

임베딩 vs 참조 결정

문자셋/콜레이션 변환

MySQL → PostgreSQL

-- MySQL 문자셋 확인
SHOW VARIABLES LIKE 'character_set%';
SELECT character_set_name, collation_name
FROM information_schema.columns WHERE table_name = 'users';

-- PostgreSQL 콜레이션
-- MySQL utf8mb4_general_ci → PostgreSQL ICU 콜레이션
CREATE COLLATION korean_ci (
    provider = icu, locale = 'ko-u-ks-level1', deterministic = false
);

-- 대소문자 무시 비교
-- MySQL: utf8mb4_general_ci (기본)
-- PostgreSQL: citext 확장 또는 LOWER() 인덱스
CREATE EXTENSION IF NOT EXISTS citext;
ALTER TABLE users ALTER COLUMN email TYPE citext;

인코딩 변환 주의사항

비가역 변환 목록

타입 매핑 검증 쿼리

-- 소스 (MySQL)
SELECT column_name, data_type, column_type,
       character_maximum_length, numeric_precision, numeric_scale,
       is_nullable, column_default, extra
FROM information_schema.columns
WHERE table_schema = 'mydb' AND table_name = 'orders'
ORDER BY ordinal_position;

-- 타깃 (PostgreSQL)
SELECT column_name, data_type, udt_name,
       character_maximum_length, numeric_precision, numeric_scale,
       is_nullable, column_default
FROM information_schema.columns
WHERE table_schema = 'public' AND table_name = 'orders'
ORDER BY ordinal_position;