database: Store work parts in seperate table

database/lib/src/database.dart

@@ -97,17 +97,18 @@ class Database extends _$Database {
   Future<WorkInfo> getWorkInfo(Work work) async {
     final id = work.id;
 
-    final composers = await composersByWork(id).get();
+    final composers = await partComposersByWork(id).get();
+    composers.insert(0, await personById(work.composer).getSingle());
     final instruments = await instrumentsByWork(id).get();
 
     final List<PartInfo> parts = [];
-    for (final part in await workParts(id).get()) {
+    for (final part in await partsByWork(id).get()) {
       parts.add(PartInfo(
-        work: part,
+        part: part,
         composer: part.composer != null
             ? await personById(part.composer).getSingle()
             : null,
-        instruments: await instrumentsByWork(id).get(),
+        instruments: await instrumentsByWorkPart(part.id).get(),
       ));
     }
 
@@ -163,32 +164,35 @@ class Database extends _$Database {
       // deleted automatically due to their foreign key constraints.
       await deleteWork(workId);
 
-      /// Insert instrumentations for a work.
-      ///
-      /// At the moment, this will also update all provided instruments, even
-      /// if they were already there previously.
-      Future<void> insertInstrumentations(
-          int workId, List<Instrument> instruments) async {
-        for (final instrument in instruments) {
-          await updateInstrument(instrument);
-          await into(instrumentations).insert(Instrumentation(
-            work: workId,
-            instrument: instrument.id,
-          ));
-        }
-      }
-
       // This will also include the composers of the work's parts.
       for (final person in workInfo.composers) {
         await updatePerson(person);
       }
 
       await into(works).insert(workInfo.work);
-      await insertInstrumentations(workId, workInfo.instruments);
+
+      // At the moment, this will also update all provided instruments, even if
+      // they were already there previously.
+      for (final instrument in workInfo.instruments) {
+        await updateInstrument(instrument);
+        await into(instrumentations).insert(Instrumentation(
+          work: workId,
+          instrument: instrument.id,
+        ));
+      }
 
       for (final partInfo in workInfo.parts) {
-        await into(works).insert(partInfo.work);
-        await insertInstrumentations(partInfo.work.id, partInfo.instruments);
+        final part = partInfo.part;
+
+        await into(workParts).insert(part);
+
+        for (final instrument in workInfo.instruments) {
+          await updateInstrument(instrument);
+          await into(partInstrumentations).insert(PartInstrumentation(
+            workPart: part.id,
+            instrument: instrument.id,
+          ));
+        }
       }
     });
   }

database/lib/src/database.moor

@@ -14,9 +14,7 @@ CREATE TABLE instruments (
 CREATE TABLE works (
     id INTEGER NOT NULL PRIMARY KEY,
     composer INTEGER REFERENCES persons(id) ON DELETE SET NULL,
-    title TEXT NOT NULL,
-    part_of INTEGER REFERENCES works(id) ON DELETE CASCADE,
-    part_index INTEGER
+    title TEXT NOT NULL
 );
 
 CREATE TABLE instrumentations (
@@ -24,6 +22,19 @@ CREATE TABLE instrumentations (
     instrument INTEGER NOT NULL REFERENCES instruments(id) ON DELETE CASCADE
 );
 
+CREATE TABLE work_parts (
+    id INTEGER NOT NULL PRIMARY KEY,
+    composer INTEGER REFERENCES persons(id) ON DELETE SET NULL,
+    title TEXT NOT NULL,
+    part_of INTEGER NOT NULL REFERENCES works(id) ON DELETE CASCADE,
+    part_index INTEGER NOT NULL
+);
+
+CREATE TABLE part_instrumentations (
+    work_part INTEGER NOT NULL REFERENCES works(id) ON DELETE CASCADE,
+    instrument INTEGER NOT NULL REFERENCES instruments(id) ON DELETE CASCADE
+);
+
 CREATE TABLE ensembles (
     id INTEGER NOT NULL PRIMARY KEY,
     name TEXT NOT NULL
@@ -66,29 +77,37 @@ SELECT * FROM instruments WHERE id = :id LIMIT 1;
 workById:
 SELECT * FROM works WHERE id = :id LIMIT 1;
 
-workParts:
-SELECT * FROM works WHERE part_of = :id ORDER BY part_index;
+partsByWork:
+SELECT * FROM work_parts WHERE part_of = :id ORDER BY part_index;
 
 worksByComposer:
-SELECT DISTINCT A.* FROM works A LEFT JOIN works B ON A.id = B.part_of
-    WHERE (A.part_of IS NULL AND A.composer = :id) OR B.composer = :id
-    ORDER BY A.title LIMIT :limit OFFSET :offset;
+SELECT DISTINCT works.* FROM works
+    JOIN work_parts ON work_parts.part_of = works.id
+    WHERE works.composer = :id OR work_parts.composer = :id
+    ORDER BY works.title LIMIT :limit OFFSET :offset;
 
 searchWorksByComposer:
-SELECT DISTINCT A.* FROM works A LEFT JOIN works B ON A.id = B.part_of
-    WHERE ((A.part_of IS NULL AND A.composer = :id) OR B.composer = :id)
-    AND A.title LIKE :search ORDER BY A.title LIMIT :limit OFFSET :offset;
+SELECT DISTINCT works.* FROM works
+    JOIN work_parts ON work_parts.part_of = works.id
+    WHERE (works.composer = :id OR work_parts.composer = :id)
+    AND works.title LIKE :search
+    ORDER BY works.title LIMIT :limit OFFSET :offset;
 
-composersByWork:
+partComposersByWork:
 SELECT DISTINCT persons.* FROM persons
-    JOIN works ON works.composer = persons.id
-    WHERE works.id = :id OR works.part_of = :id;
+    JOIN work_parts ON work_parts.composer = persons.id
+    WHERE work_parts.part_of = :id;
 
 instrumentsByWork:
 SELECT instruments.* FROM instrumentations
-    JOIN instruments ON instrumentations.instrument=instruments.id
+    JOIN instruments ON instrumentations.instrument = instruments.id
     WHERE instrumentations.work = :workId;
 
+instrumentsByWorkPart:
+SELECT instruments.* FROM part_instrumentations
+    JOIN instruments ON part_instrumentations.instrument = instruments.id
+    WHERE part_instrumentations.work_part = :id;
+
 allEnsembles:
 SELECT * FROM ensembles ORDER BY name LIMIT :limit OFFSET :offset;
 

database/lib/src/info.dart

@@ -3,7 +3,7 @@ import 'database.dart';
 /// A bundle of all available information on a work part.
 class PartInfo {
   /// The work part itself.
-  final Work work;
+  final WorkPart part;
 
   /// A list of instruments.
   ///
@@ -16,13 +16,13 @@ class PartInfo {
   final Person composer;
 
   PartInfo({
-    this.work,
+    this.part,
     this.instruments,
     this.composer,
   });
 
   factory PartInfo.fromJson(Map<String, dynamic> json) => PartInfo(
-        work: Work.fromJson(json['work']),
+        part: WorkPart.fromJson(json['part']),
         instruments: json['instruments']
             .map<Instrument>((j) => Instrument.fromJson(j))
             .toList(),
@@ -31,7 +31,7 @@ class PartInfo {
       );
 
   Map<String, dynamic> toJson() => {
-        'work': work.toJson(),
+        'part': part.toJson(),
         'instruments': instruments.map((i) => i.toJson()).toList(),
         'composers': composer?.toJson(),
       };