基于Room的sql操作

如果字段发生变化 set get 方法(未显示)也要更新 否则找不到

@Entity(tableName = "marquee")
public class Marquee {
    @PrimaryKey
    private int marqueeid;
    private String message;
    private String startdate;
    private String stopdate;
    @Ignore
    private int type;
    private int status;
    @Ignore
    private List<MarqueeTime> playtimes;

插入

    <!-- 单个插入 -->
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertMarquee(Marquee marquee);
    <!-- 批量插入 -->
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertAll(List<Marquee> marquees);

更新

   <!-- 更新对象 -->
  @Update(onConflict = OnConflictStrategy.REPLACE)
  void updateMarquee(Marquee marquee);
  <!-- 更新某个字段 -->
  @Query("update marquee set message=:msg where marqueeId=:id")
  void update(String msg,int id);

删除

   <!-- 删除单个 -->
   @Delete
   void deleteMarquee(Marquee marquee);
   <!-- 条件删除 -->
   @Query("delete from marquee  where marqueeId=:id")
   void deleteMarquee(int id);
   <!-- 删除集合 -->
   @Delete
   void deleteAll(List<Marquee > marquees);
   <!-- 删除全部 -->
   @Query("delete from marquee")
   void deleteAllMarquees();

查询

    //有效日期内的检索
    @Query("select * from marquee where date(:currentDate) between date(startDate) and date(stopDate) and status =0")
    List<Marquee> queryValidMarquee(String currentDate);
    <!-- 根据某个字段升序 -->
    @Query("select * from marquee order by marqueeId asc")
    LiveData<List<Marquee>> loadMarquees();
   <!-- 限定查询数量 -->
     @Query("select * from ward limit 1")
    LiveData<Marquee> loadMarquee();
    <!--比较查询  -->
    @Query("select * from marquee where marqueeId in (:ids)")
    List<Marquee> getMarqueeById(String... ids);