SQLite 에서 ROOM 까지 (11) - ROOM 을 이용한 CRUD

이번 포스팅에서는 Room 을 이용한 CRUD 에 대해 알아보자.

CREATE(INSERT), READ(SELECT), UPDATE(UPDATE), DELETE(DELETE)

 

참고로, 지난 포스팅 내용은 하단과 같다.

- UI, DB 생성, CRUD, column 추가, DB 확인

[Android/Database] - SQLite 에서 ROOM 까지 (2) - UI 구성

[Android/Database] - SQLite 에서 ROOM 까지 (3) - SQLiteOpenHelper

[Android/Database] - SQLite 에서 ROOM 까지 (4) - SQLite 를 이용한 CRUD

[Android/Database] - SQLite 에서 ROOM 까지 (5) - SQLite 로 생성된 기존 DB 에 column 추가하기

[Android/Database] - SQLite 에서 ROOM 까지 (6) - DB 확인하기

- ROOM, ROOM 의 3구성요소 추가, Repository, ViewModel 추가, migation 설정

[Android/Database] - SQLite 에서 ROOM 까지 (7) - ROOM 이란?

[Android/Database] - SQLite 에서 ROOM 까지 (8) - ROOM 의 3 구성요소(Database, Entity, Dao) 추가하기

[Android/Database] - SQLite 에서 ROOM 까지 (9) - Architecture Components 구성을 위한 Repository, ViewModel 추가하기

[Android/Database] - SQLite 에서 ROOM 까지 (10) - SQLite 에서 ROOM 으로 migration 설정하기

DB table

하단은 예제에 사용할 DB table 이다.

Field	Type	Property
ID (StudentEntry._ID)	INTEGER (not null)	primary key auto increment
학년 (StudentEntry.GRADE)	INTEGER (not null)
학번 (StudentEntry.NUMBER)	INTEGER (not null)
이름 (StudentEntry.NAME)	TEXT
나이 (StudentEntry.AGE)	INTEGER (not null)

Create (INSERT)

사용자 입력값을 DB 에 삽입.

	private void insertData(int a_grade, int a_number, String a_strName, int a_age) {
	PhStudentEntity studentEntity = new PhStudentEntity();
	studentEntity.setId(0);
	studentEntity.setGrade(a_grade);
	studentEntity.setNumber(a_number);
	studentEntity.setName(a_strName);
	studentEntity.setAge(a_age);
	// DB 삽입
	mViewModel.insert(studentEntity);
	}

view raw PhMainActivity.java hosted with ❤ by GitHub

 

	public void insert(PhStudentEntity a_studentEntity) {
	mRepository.insert(a_studentEntity);
	}

view raw PhStudentViewModel.java hosted with ❤ by GitHub

 

	public void insert(PhStudentEntity a_studentEntity) {
	new insertAsyncTask(mStudentDao).execute(a_studentEntity);
	}
	private static class insertAsyncTask extends AsyncTask<PhStudentEntity, Void, Void> {
	private PhStudentDao asyncTaskDao;
	insertAsyncTask(PhStudentDao a_dao) {
	asyncTaskDao = a_dao;
	}
	@Override
	protected Void doInBackground(final PhStudentEntity... studentEntities) {
	asyncTaskDao.insert(studentEntities[0]);
	return null;
	}
	}

view raw PhStudentRepository.java hosted with ❤ by GitHub

 

	@Dao
	public interface PhStudentDao {
	@Insert(onConflict = OnConflictStrategy.REPLACE)
	Long insert(PhStudentEntity a_studentEntity);
	}

view raw PhStudentDao.java hosted with ❤ by GitHub

Read (SELECT)

DB 전체를 query.

	private List getAllData() {
	PhUpdateInterface updateInterface = (a_studentEntityList) -> {
	mItemList.addAll(a_studentEntityList);
	mRecyclerAdapter.notifyDataSetChanged();
	};
	return mViewModel.getAllStudents(updateInterface);
	}

view raw PhMainActivity.java hosted with ❤ by GitHub

 

	public interface PhUpdateInterface {
	void onUpdate(List<PhStudentEntity> a_studentEntityList);
	}

view raw PhUpdateInterface.java hosted with ❤ by GitHub

 

	public List<PhStudentEntity> getAllStudents(PhUpdateInterface a_updateInterface) {
	return mRepository.getAllStudents(a_updateInterface);
	}

view raw PhStudentViewModel.java hosted with ❤ by GitHub

 

	public List<PhStudentEntity> getAllStudents(PhUpdateInterface a_updateInterface) {
	List<PhStudentEntity> students = null;
	try {
	students = new getAllUsersAsyncTask(mStudentDao, a_updateInterface).execute().get();
	} catch (ExecutionException | InterruptedException e) {
	e.printStackTrace();
	}
	return students;
	}
	private static class getAllUsersAsyncTask extends AsyncTask<Void, Void, List<PhStudentEntity>> {
	private PhStudentDao mAsyncTaskDao;
	private PhUpdateInterface mUpdateInterface;
	getAllUsersAsyncTask(PhStudentDao a_dao, PhUpdateInterface a_updateInterface) {
	mAsyncTaskDao = a_dao;
	mUpdateInterface = a_updateInterface;
	}
	@Override
	protected List<PhStudentEntity> doInBackground(Void... url) {
	return mAsyncTaskDao.getAllStudents();
	}
	@Override
	protected void onPostExecute(List<PhStudentEntity> a_studentEntityList) {
	mUpdateInterface.onUpdate(a_studentEntityList);
	}
	}

view raw PhStudentRepository.java hosted with ❤ by GitHub

 

	@Dao
	public interface PhStudentDao {
	@Query("SELECT * FROM " + StudentEntry.TABLE_NAME)
	List<PhStudentEntity> getAllStudents();
	}

view raw PhStudentDao.java hosted with ❤ by GitHub

Update (UPDATE)

선택한 column 을 사용자 입력값으로 DB 갱신.

DAO 에 '@Insert(onConflict = OnConflictStrategy.REPLACE)' option 을 사용해 CREATE 과정과 동일

 

	private void updateData(int a_id, int a_grade, int a_number, String a_strName, int a_age) {
	PhStudentEntity studentEntity = new PhStudentEntity();
	studentEntity.setId(a_id);
	studentEntity.setGrade(a_grade);
	studentEntity.setNumber(a_number);
	studentEntity.setName(a_strName);
	studentEntity.setAge(a_age);
	// DB 갱신
	mViewModel.insert(studentEntity);
	}

view raw PhMainActivity.java hosted with ❤ by GitHub

Delete (DELETE)

선택한 column 을 DB 에서 삭제.

	private void deleteData(int a_id) {
	// DB 삭제
	mViewModel.deleteById(a_id);
	}

view raw PhMainActivity.java hosted with ❤ by GitHub

 

	public void deleteById(int a_id) {
	mRepository.deleteById(a_id);
	}

view raw PhStudentViewModel.java hosted with ❤ by GitHub

 

	public void deleteById(int a_id) {
	new deleteAsyncTask(mStudentDao).execute(a_id);
	}
	private static class deleteAsyncTask extends AsyncTask<Integer, Void, Void> {
	private PhStudentDao asyncTaskDao;
	deleteAsyncTask(PhStudentDao a_dao) {
	asyncTaskDao = a_dao;
	}
	@Override
	protected Void doInBackground(final Integer... a_id) {
	asyncTaskDao.deleteById(a_id[0]);
	return null;
	}
	}

view raw PhStudentRepository.java hosted with ❤ by GitHub

 

	@Dao
	public interface PhStudentDao {
	@Query("DELETE FROM " + StudentEntry.TABLE_NAME + " WHERE _id = :a_id")
	void deleteById(int a_id);
	}

view raw PhStudentDao.java hosted with ❤ by GitHub

Source code

https://github.com/parkho79/FromSQLiteToRoom_3