small refactor, better dao thigns

lib/daos/activities_dao.dart

@@ -11,8 +11,8 @@ class ActivitiesDao extends DatabaseAccessor<AppDatabase> with _$ActivitiesDaoMi
     return await select(activities).get();
   }
 
-  Future<List<Activity>> find(int id) async {
-    return await (select(activities)..where((activity) => activity.id.equals(id) )).get();
+  Future<Activity> find(int id) async {
+    return await (select(activities)..where((activity) => activity.id.equals(id) )).getSingle();
   }
 
   Future<List<Activity>> sessionActivities(int id) async {

lib/daos/media_items_dao.dart

@@ -11,11 +11,31 @@ class MediaItemsDao extends DatabaseAccessor<AppDatabase> with _$MediaItemsDaoMi
     return await select(mediaItems).get();
   }
 
-  Future<List<MediaItem>> find(int id) async {
-    return await (select(mediaItems)..where((mediaItem) => mediaItem.id.equals(id) )).get();
+  Future<MediaItem> find(int id) async {
+    return await (select(mediaItems)..where((mediaItem) => mediaItem.id.equals(id) )).getSingle();
   }
 
-  Future<List<MediaItem>> mediaItemsFromSession(Session session) async {
+  Future<List<MediaItem>> fromActivity(Activity activity) async {
+    final result = select(db.objectMediaItems).join(
+      [
+        innerJoin(
+          db.mediaItems,
+          db.mediaItems.id.equalsExp(db.objectMediaItems.mediaId),
+        ),
+      ],
+    )
+      ..where(
+          db.objectMediaItems.objectType.equals(ObjectType.activities.name))
+      ..where(db.objectMediaItems.objectId.equals(activity.id));
+
+    final mediaItems = (await result.get())
+        .map((e) => e.readTable(db.mediaItems))
+        .toList();
+
+    return mediaItems;
+  }
+
+  Future<List<MediaItem>> fromSession(Session session) async {
     final result = select(db.objectMediaItems).join(
       [
         innerJoin(

lib/daos/session_activities_dao.dart

@@ -11,11 +11,11 @@ class SessionActivitiesDao extends DatabaseAccessor<AppDatabase> with _$SessionA
     return await select(sessionActivities).get();
   }
 
-  Future<List<SessionActivity>> find(int id) async {
-    return await (select(sessionActivities)..where((sessionActivity) => sessionActivity.id.equals(id) )).get();
+  Future<SessionActivity> find(int id) async {
+    return await (select(sessionActivities)..where((sessionActivity) => sessionActivity.id.equals(id) )).getSingle();
   }
 
-  Future<List<SessionActivity>> sessionActivitiesBySessionId(int id) async {
+  Future<List<SessionActivity>> fromSessionId(int id) async {
     final result = db.managers.sessionActivities
         .filter((sessionActivity) => sessionActivity.sessionId.id(id));
 

lib/daos/sessions_dao.dart

@@ -11,7 +11,7 @@ class SessionsDao extends DatabaseAccessor<AppDatabase> with _$SessionsDaoMixin
     return await select(sessions).get();
   }
 
-  Future<List<Session>> find(int id) async {
-    return await (select(sessions)..where((session) => session.id.equals(id) )).get();
+  Future<Session> find(int id) async {
+    return await (select(sessions)..where((session) => session.id.equals(id) )).getSingle();
   }
 }