Question

这是sqlite查询，我想要此房间数据库这里首先尝试插入数据（如果数据存在），然后使用id更新数据

INSERT INTO books(id, title, author, year_published)  VALUES(@id, @title, @author, @year_published)
 ON DUPLICATE KEY UPDATE title = @title,  author = @author;

Answer 1

Room支持@RawQuery批注以在运行时构造查询。所以你需要：

@Dao
interface BooksDao{
    @RawQuery
    List<Book> books(SupportSQLiteQuery query);
}

并以旧学校风格创建查询：

String queryString = "here is your query";
List<Object> args = new ArrayList(); // here is your args for your query

然后执行您的查询：

SimpleSQLiteQuery query = new SimpleSQLiteQuery(queryString, args.toArray());
List<Book> result = booksDao.books(query);

Answer 2

您可以通过 OnConflictStrategy.REPLACE

实现此目标

@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insertBooks(vararg books: Book)

并且您必须将ID id 指定为主键

@Entity(tableName = "book_table")
data class Book(
    @PrimaryKey val id: String,
    val title: String,
    val author: String,
    val year_published: Int
)

如何在会议室数据库中实现sqlite查询？

2 个答案: