Fetch relations using floor

article_dao.dart

@Query('SELECT * FROM article ORDER BY publishedAt DESC')
Stream<List<Article>> getAllArticles();

@Query('SELECT Author.*, _junction.articleId as articleId FROM ArticleAuthor AS _junction inner join Author ON (_junction.authorId = Author.id) WHERE _junction.articleId IN (:ids)')
Future<List<AuthorArticleId>> getAuthorsFromArticles(List<int> ids);

Stream<List<ArticleWithAuthor>> getAllArticlesWithAuthors() {
  final stream = getAllArticles();
  final controller = StreamController<List<ArticleWithAuthor>>.broadcast();

  Future<void> getInternalAuthors(List<Article> articles) async {
    final ids = articles.map((it) => it.id).toList();
    final authors = await getAuthorsFromArticles(ids);
    final result = articles.map((element) {
      final data = authors.firstWhere((it) => it.articleId == element.id);
      Author author;
      if (data != null) {
        author = Author(data.id, data.name, data.slug, data.avatar);
      }
      return ArticleWithAuthor(
        element,
        author
      );
    }).toList();
    controller.add(result);
  }

  stream.listen(
    (articles) async {
      getInternalAuthors(articles);
    },
    onDone: () => controller.close()
  );
  return controller.stream;
}

author_article_id.dart

@DatabaseView('SELECT Author.*, _junction.articleId as articleId FROM ArticleAuthor AS _junction inner join Author ON (_junction.authorId = Author.id)')
class AuthorArticleId {
  final int id;
  final String name;
  final String slug;
  final String avatar;
  final int articleId;

  AuthorArticleId(this.id, this.name, this.slug, this.avatar, this.articleId);
}