Fix album patch

server/db/Album.ts

@@ -174,9 +174,9 @@ export async function modifyAlbum(userId: number, albumId: number, album: Album,
         const artistIdsPromise: Promise<number[] | undefined> =
             album.artistIds ?
                 trx.select('artistId')
-                    .from('artists_albums')
-                    .whereIn('artistId', album.artistIds)
-                    .then((as: any) => as.map((a: any) => a['artistId']))
+                    .from('artists')
+                    .whereIn('id', album.artistIds)
+                    .then((as: any) => as.map((a: any) => a['id']))
                 : (async () => undefined)();
 
         // Start retrieving tracks if we are modifying those.
@@ -192,18 +192,18 @@ export async function modifyAlbum(userId: number, albumId: number, album: Album,
         const tagIdsPromise =
             album.tagIds ?
                 trx.select('id')
-                    .from('albums_tags')
-                    .whereIn('tagId', album.tagIds)
-                    .then((ts: any) => ts.map((t: any) => t['tagId'])) :
+                    .from('tags')
+                    .whereIn('id', album.tagIds)
+                    .then((ts: any) => ts.map((t: any) => t['id'])) :
                 (async () => undefined)();
 
         // Wait for the requests to finish.
         var [oldAlbum, artists, tags, tracks] = await Promise.all([albumIdPromise, artistIdsPromise, tagIdsPromise, trackIdsPromise]);;
 
         // Check that we found all objects we need.
-        if ((!artists || !_.isEqual(artists.sort(), (album.artistIds || []).sort())) ||
-            (!tags || !_.isEqual(tags.sort(), (album.tagIds || []).sort())) ||
-            (!tracks || !_.isEqual(tracks.sort(), (album.trackIds || []).sort())) ||
+        if ((album.artistIds && (!artists || !_.isEqual(artists.sort(), (album.artistIds || []).sort()))) ||
+            (album.tagIds && (!tags || !_.isEqual(tags.sort(), (album.tagIds || []).sort()))) ||
+            (album.trackIds && (!tracks || !_.isEqual(tracks.sort(), (album.trackIds || []).sort()))) ||
             !oldAlbum) {
             throw makeNotFoundError();
         }