Spring Data JDBC

DROP TABLE IF EXISTS github;
DROP TABLE IF EXISTS game;
DROP TABLE IF EXISTS user;

CREATE TABLE IF NOT EXISTS user (id int auto_increment primary key, email varchar(64) unique, created_date datetime);

CREATE TABLE IF NOT EXISTS github (
  user int primary key references user(id),
  email varchar(64),
  github_id varchar(64)
);

CREATE TABLE IF NOT EXISTS game(
    id int auto_increment primary key,
    user int references user(id),
    user_key int,
    game_name varchar(64)
)
Java
복사

나. One to One

1) 부모 객체

•

Aggregate Root 객체에 자식 객체를 맵핑함

public class User {
	private Github github;

	public Github getGithub(){return github;} 
	public void setGithub(Github github){this.github = github}
}
Java
복사

2) 자식 객체

•

primary key는 부모 객체가 됨

public class Github {
    @Id
    private Long user;
    private String email;
    private String githubId;

		// 생략
}
Java
복사

다. One to Many

1) 부모 객체

•

부모 객체에서 자식 객체의 삽입 및 삭제 관리

public class User {

    @Id
    private Long id;
    private List<Game> games = new ArrayList<>()

    public void addGame(Game game) {
        this.games.add(game);
    }
    public void removeAllGame() {
        this.games.clear();
    }
    public List<Game> getGames() {
        return this.games;
    }
}
Java
복사

2) 자식 객체

•

부모 객체에 대해 int 타입으로 외래키를 받는 부분이 존재함

→ 이게 외래키가 아닌데? Test Code 돌려보면 무조건 0으로만 찍히는데 무슨 역할을 하는거지?

public class Game {

    @Id
    private Long id;
    private int user;
    private String gameName;

    public Game(String gameName) {
        this.gameName = gameName;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public void setUser(int user) {
        this.user = user;
    }

    public void setGameName(String gameName) {
        this.gameName = gameName;
    }

    public Long getId() {
        return id;
    }

    public int getUser() {
        return user;
    }

    public String getGameName() {
        return gameName;
    }
}
Java
복사

3) 기타

•

user:game(1:N 관계)를 맵핑하기 위해 schema.sql의 game table 부분에 user_key 삽입함

라. Many to Many

@Autowired
private ApplicationContext ctx;
Plain Text
복사

@SpringBootTest
class SpringBootDemoApplicationTests {

   @Autowired
   private ApplicationContext ctx;

   @Autowired
   private UserRepository userRepo;

   private Logger logger = LoggerFactory.getLogger(SpringBootDemoApplicationTests.class);

   @Test
   void contextLoads() {
assertThat(ctx).isNotNull();
      logger.debug("ApplicationContext is not null");
   }

   @Test
   void LoggerNotNull() {
assertThat(logger).isNotNull();
      logger.debug("Logger OK");
   }
}
Plain Text
복사

마. Spring에 MySQL 연동

1) mysql-connector 추가

// build.gradle

dependencies {
   implementation 'org.springframework.boot:spring-boot-starter'
   runtimeOnly 'mysql:mysql-connector-java'
   testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
Java
복사

2) mysql connection 설정

// application.properties

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3309/test_table?serverTimezone=UTC&characterEncoding=UTF-8
spring.datasource.username=dev
spring.datasource.password=pass
Java
복사

3) data.sql, schema.sql 적용

// application.properties

spring.datasource.initialization-mode=always
Java
복사

Reference

•

Spring에 MySQL 연동하기, https://velog.io/@ddusi/Spring-1