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| //实体类,每个字段都是数据库中的一列
@Entity(tableName = "article")
data class ArticleDetial(
@PrimaryKey(autoGenerate = true)
val id : Int,
val author: String,
val title: String,
val content: String)
//Dao接口 操作数据库的主要接口
@Dao
interface ArticleDao {
@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insertArticle(article : ArticleDetial)
@Delete()
fun deleteArticle(article:ArticleDetial)
@Query("DELETE FROM article")
fun deleteAllArticles()
@Query("SELECT * FROM article ORDER BY id DESC")
fun queryArticle(): Single<List<ArticleDetial>>
@Query("SELECT * FROM article WHERE id IN (:range)")
fun queryRange(range:IntArray):Flowable<List<ArticleDetial>>
}
//数据库S,为应用创建数据库
@Database(entities = {ArticleDetial.class},version=1)
public abstract class AppDatabase extends RoomDatabase{
public abstract ArticleDao articleDao();
}
val db : AppDatabase = Room.databaseBuilder(context, AppDatabase::class.java, "articles").build()
创建数据库
|
