[Android Java] Room DB 사용하기

1. Code

A. UrlDao

@Dao
public interface UrlDao {
    //입력
    @Insert(onConflict = REPLACE)
    void insert(UrlData urlData);
    //삭제(오버로딩 삭제)
    @Delete
    void delete(UrlData urlData);
    //전체삭제
    @Delete
    void reset(List<UrlData> urlData);
    //값 선택
    @Query("SELECT * FROM urlData where content = :sContent")
    UrlData findById(String sContent);
}

 

B. UrlData

@Entity(tableName = "urlData")
    public class UrlData implements Serializable {

        //    @PrimaryKey(autoGenerate = false)
//    private int id;
        @NonNull
        @PrimaryKey
        private String content;

        //    @ColumnInfo(name = "content")
//    private String content;
        @ColumnInfo(name = "image")
        private String image;
        @ColumnInfo(name = "title")
        private String title;
        @ColumnInfo(name = "description")
        private String description;

        //Id
//    public void setId(int id) {this.id = id;}
//    public int getId() {return id; }
        //Content
        public void setContent(String content){this.content = content; }
        public String getContent(){return content; }
        //Image
        public void setImage(String image){this.image = image; }
        public String getImage(){return image; }
        //Title
        public void setTitle(String title){ this.title = title; }
        public String getTitle(){return title; }
        //Description
        public void setDescription(String description){this.description = description; }
        public String getDescription(){return description; }

}        

Primary Key에 Int넣을시 autoGenerate = true 하면 0부터 차례로 데이터 들어감
Primary Key에 String넣을시 @NonNull 넣어야함

 

C. UrlRoomDB

@Database(entities = {UrlData.class}, version = 1, exportSchema = false)
public abstract class UrlRoomDB extends RoomDatabase {

    private static UrlRoomDB database;

    private static String DATABASE_NAME = "database";

    public synchronized static UrlRoomDB getInstance(Context context){
        if (database == null){
            database = Room.databaseBuilder(context.getApplicationContext(), UrlRoomDB.class, DATABASE_NAME)
                    .allowMainThreadQueries()
                    .fallbackToDestructiveMigration()
                    .build();
        }
        return database;
    }
    public abstract UrlDao urlDao();
}

 

2. 생성

    public UrlRoomDB database;
    public UrlData data;
    
    //RoomDB 활성화
    database = UrlRoomDB.getInstance(ChatViewActivity.this);
    //데이터 찾아서 가져오기
    data = database.urlDao().findById(event.list.get(0).trim());
    
    //데이터 클래스에 데이터 넣기
    data.setContent("스트링값");
    //데이터 클래스에 데이터 빼기
    data.getContent;
    
    //RoomDB 20221107 Bell RoomDB에 데이터 넣기
    InsertUrlRoomDB(response, image, title, description);
    

 

 

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Reference

https://stickode.tistory.com/103
https://todaycode.tistory.com/39
https://developer.android.com/training/data-storage/room?hl=ko#kts