diff --git a/packages/firebase_data_connect/firebase_data_connect/example/dataconnect/connector/queries.gql b/packages/firebase_data_connect/firebase_data_connect/example/dataconnect/connector/queries.gql
index c4006e2ee0b7..3c1ce8191a13 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/dataconnect/connector/queries.gql
+++ b/packages/firebase_data_connect/firebase_data_connect/example/dataconnect/connector/queries.gql
@@ -6,6 +6,7 @@ query ListMovies @auth(level: USER) {
     directed_by: people_via_DirectedBy {
       name
     }
+    rating
   }
 }
 
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/integration_test/generation_e2e.dart b/packages/firebase_data_connect/firebase_data_connect/example/integration_test/generation_e2e.dart
index 242acecf666d..6f6aa6afb363 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/integration_test/generation_e2e.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/integration_test/generation_e2e.dart
@@ -37,14 +37,14 @@ void runGenerationTest() {
           rating: 4.5,
         );
         expect(ref, isNotNull);
-        expect(ref.execute, isNotNull);
+        expect(ref.build().execute, isNotNull);
       });
 
       testWidgets('should have generated correct QueryRef',
           (WidgetTester tester) async {
         final ref = MoviesConnector.instance.listMovies.ref();
         expect(ref, isNotNull);
-        expect(ref.execute, isNotNull);
+        expect(ref.build().execute, isNotNull);
       });
 
       testWidgets('should have generated correct MutationRef using name',
@@ -53,7 +53,7 @@ void runGenerationTest() {
           name: 'Keanu Reeves',
         );
         expect(ref, isNotNull);
-        expect(ref.execute, isNotNull);
+        expect(ref.build().execute, isNotNull);
       });
 
       testWidgets('should have generated correct MutationRef using nested id',
@@ -63,7 +63,7 @@ void runGenerationTest() {
           personId: AddDirectorToMovieVariablesPersonId(id: 'personId'),
         );
         expect(ref, isNotNull);
-        expect(ref.execute, isNotNull);
+        expect(ref.build().execute, isNotNull);
       });
     },
   );
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/integration_test/listen_e2e.dart b/packages/firebase_data_connect/firebase_data_connect/example/integration_test/listen_e2e.dart
index a41c3668d525..9b7a96480c91 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/integration_test/listen_e2e.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/integration_test/listen_e2e.dart
@@ -21,7 +21,7 @@ void runListenTests() {
       testWidgets('should be able to listen to the list of movies',
           (WidgetTester tester) async {
         final initialValue =
-            await MoviesConnector.instance.listMovies.ref().execute();
+            await MoviesConnector.instance.listMovies.ref().build().execute();
         expect(initialValue.data.movies.length, 0,
             reason: 'Initial movie list should be empty');
 
@@ -31,6 +31,7 @@ void runListenTests() {
 
         final listener = MoviesConnector.instance.listMovies
             .ref()
+            .build()
             .subscribe()
             .listen((value) {
           final movies = value.data.movies;
@@ -60,9 +61,10 @@ void runListenTests() {
               releaseYear: 1999,
               rating: 4.5,
             )
+            .build()
             .execute();
 
-        await MoviesConnector.instance.listMovies.ref().execute();
+        await MoviesConnector.instance.listMovies.ref().build().execute();
 
         // Wait for the listener to receive the movie update
         final bool hasListenerReceived = await hasBeenListened.future;
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/integration_test/query_e2e.dart b/packages/firebase_data_connect/firebase_data_connect/example/integration_test/query_e2e.dart
index 55fd6e78de11..61e23e28dd5a 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/integration_test/query_e2e.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/integration_test/query_e2e.dart
@@ -7,10 +7,14 @@ import 'package:firebase_data_connect_example/generated/movies.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 Future<void> deleteAllMovies() async {
-  final value = await MoviesConnector.instance.listMovies.ref().execute();
+  final value =
+      await MoviesConnector.instance.listMovies.ref().build().execute();
   final result = value.data;
   for (var movie in result.movies) {
-    await MoviesConnector.instance.deleteMovie.ref(id: movie.id).execute();
+    await MoviesConnector.instance.deleteMovie
+        .ref(id: movie.id)
+        .build()
+        .execute();
   }
 }
 
@@ -23,70 +27,81 @@ void runQueryTests() {
       });
 
       testWidgets('can query', (WidgetTester tester) async {
-        final value = await MoviesConnector.instance.listMovies.ref().execute();
+        final value =
+            await MoviesConnector.instance.listMovies.ref().build().execute();
 
         final result = value.data;
         expect(result.movies.length, 0);
       });
 
       testWidgets('can add a movie', (WidgetTester tester) async {
-        MutationRef ref = MoviesConnector.instance.createMovie.ref(
-          genre: 'Action',
-          title: 'The Matrix',
-          releaseYear: 1999,
-          rating: 4.5,
-        );
+        MutationRef ref = MoviesConnector.instance.createMovie
+            .ref(
+              genre: 'Action',
+              title: 'The Matrix',
+              releaseYear: 1999,
+              rating: 4.5,
+            )
+            .build();
 
         await ref.execute();
 
-        final value = await MoviesConnector.instance.listMovies.ref().execute();
+        final value =
+            await MoviesConnector.instance.listMovies.ref().build().execute();
         final result = value.data;
         expect(result.movies.length, 1);
         expect(result.movies[0].title, 'The Matrix');
       });
 
       testWidgets('can add a director to a movie', (WidgetTester tester) async {
-        MutationRef ref = MoviesConnector.instance.addPerson.ref(
-          name: 'Keanu Reeves',
-        );
+        MutationRef ref = MoviesConnector.instance.addPerson
+            .ref(
+              name: 'Keanu Reeves',
+            )
+            .build();
 
         await ref.execute();
 
         final personId =
-            (await MoviesConnector.instance.listPersons.ref().execute())
+            (await MoviesConnector.instance.listPersons.ref().build().execute())
                 .data
                 .people[0]
                 .id;
 
-        final value = await MoviesConnector.instance.listMovies.ref().execute();
+        final value =
+            await MoviesConnector.instance.listMovies.ref().build().execute();
         final result = value.data;
         expect(result.movies.length, 0);
 
-        ref = MoviesConnector.instance.createMovie.ref(
-          genre: 'Action',
-          title: 'The Matrix',
-          releaseYear: 1999,
-          rating: 4.5,
-        );
+        ref = MoviesConnector.instance.createMovie
+            .ref(
+              genre: 'Action',
+              title: 'The Matrix',
+              releaseYear: 1999,
+              rating: 4.5,
+            )
+            .build();
 
         await ref.execute();
 
         final value2 =
-            await MoviesConnector.instance.listMovies.ref().execute();
+            await MoviesConnector.instance.listMovies.ref().build().execute();
         final result2 = value2.data;
         expect(result2.movies.length, 1);
 
         final movieId = result2.movies[0].id;
 
-        ref = MoviesConnector.instance.addDirectorToMovie.ref(
-          movieId: movieId,
-          personId: AddDirectorToMovieVariablesPersonId(id: personId),
-        );
+        ref = MoviesConnector.instance.addDirectorToMovie
+            .ref(
+              movieId: movieId,
+              personId: AddDirectorToMovieVariablesPersonId(id: personId),
+            )
+            .build();
 
         await ref.execute();
 
         final value3 =
-            await MoviesConnector.instance.listMovies.ref().execute();
+            await MoviesConnector.instance.listMovies.ref().build().execute();
         final result3 = value3.data;
         expect(result3.movies.length, 1);
         expect(result3.movies[0].directed_by.length, 1);
@@ -94,27 +109,30 @@ void runQueryTests() {
       });
 
       testWidgets('can delete a movie', (WidgetTester tester) async {
-        MutationRef ref = MoviesConnector.instance.createMovie.ref(
-          genre: 'Action',
-          title: 'The Matrix',
-          releaseYear: 1999,
-          rating: 4.5,
-        );
+        MutationRef ref = MoviesConnector.instance.createMovie
+            .ref(
+              genre: 'Action',
+              title: 'The Matrix',
+              releaseYear: 1999,
+              rating: 4.5,
+            )
+            .build();
 
         await ref.execute();
 
-        final value = await MoviesConnector.instance.listMovies.ref().execute();
+        final value =
+            await MoviesConnector.instance.listMovies.ref().build().execute();
         final result = value.data;
         expect(result.movies.length, 1);
 
         final movieId = result.movies[0].id;
 
-        ref = MoviesConnector.instance.deleteMovie.ref(id: movieId);
+        ref = MoviesConnector.instance.deleteMovie.ref(id: movieId).build();
 
         await ref.execute();
 
         final value2 =
-            await MoviesConnector.instance.listMovies.ref().execute();
+            await MoviesConnector.instance.listMovies.ref().build().execute();
         final result2 = value2.data;
         expect(result2.movies.length, 0);
       });
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_date_and_timestamp.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_date_and_timestamp.dart
index d8ddb7c80a7b..2ecb8a2d26a3 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_date_and_timestamp.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_date_and_timestamp.dart
@@ -1,25 +1,44 @@
 part of movies;
 
-class AddDateAndTimestamp {
-  String name = "addDateAndTimestamp";
-  AddDateAndTimestamp({required this.dataConnect});
+class AddDateAndTimestampVariablesBuilder {
+  DateTime date;
+  Timestamp timestamp;
+
+  FirebaseDataConnect dataConnect;
 
+  AddDateAndTimestampVariablesBuilder(
+    this.dataConnect, {
+    required DateTime this.date,
+    required Timestamp this.timestamp,
+  });
   Deserializer<AddDateAndTimestampData> dataDeserializer = (String json) =>
       AddDateAndTimestampData.fromJson(
           jsonDecode(json) as Map<String, dynamic>);
   Serializer<AddDateAndTimestampVariables> varsSerializer =
       (AddDateAndTimestampVariables vars) => jsonEncode(vars.toJson());
-  MutationRef<AddDateAndTimestampData, AddDateAndTimestampVariables> ref({
-    required DateTime date,
-    required Timestamp timestamp,
-  }) {
+  MutationRef<AddDateAndTimestampData, AddDateAndTimestampVariables> build() {
     AddDateAndTimestampVariables vars = AddDateAndTimestampVariables(
       date: date,
       timestamp: timestamp,
     );
 
     return dataConnect.mutation(
-        this.name, dataDeserializer, varsSerializer, vars);
+        "addDateAndTimestamp", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class AddDateAndTimestamp {
+  String name = "addDateAndTimestamp";
+  AddDateAndTimestamp({required this.dataConnect});
+  AddDateAndTimestampVariablesBuilder ref({
+    required DateTime date,
+    required Timestamp timestamp,
+  }) {
+    return AddDateAndTimestampVariablesBuilder(
+      dataConnect,
+      date: date,
+      timestamp: timestamp,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -28,6 +47,7 @@ class AddDateAndTimestamp {
 class AddDateAndTimestampTimestampHolderInsert {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddDateAndTimestampTimestampHolderInsert.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -41,14 +61,13 @@ class AddDateAndTimestampTimestampHolderInsert {
 
   AddDateAndTimestampTimestampHolderInsert({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddDateAndTimestampData {
   AddDateAndTimestampTimestampHolderInsert timestampHolder_insert;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddDateAndTimestampData.fromJson(Map<String, dynamic> json)
       : timestampHolder_insert =
             AddDateAndTimestampTimestampHolderInsert.fromJson(
@@ -64,9 +83,7 @@ class AddDateAndTimestampData {
 
   AddDateAndTimestampData({
     required this.timestampHolder_insert,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddDateAndTimestampVariables {
@@ -74,6 +91,7 @@ class AddDateAndTimestampVariables {
 
   Timestamp timestamp;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddDateAndTimestampVariables.fromJson(Map<String, dynamic> json)
       : date = nativeFromJson<DateTime>(json['date']),
         timestamp = Timestamp.fromJson(json['timestamp']) {}
@@ -91,7 +109,5 @@ class AddDateAndTimestampVariables {
   AddDateAndTimestampVariables({
     required this.date,
     required this.timestamp,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_director_to_movie.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_director_to_movie.dart
index e16570853506..2632d441039f 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_director_to_movie.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_director_to_movie.dart
@@ -1,24 +1,43 @@
 part of movies;
 
-class AddDirectorToMovie {
-  String name = "addDirectorToMovie";
-  AddDirectorToMovie({required this.dataConnect});
+class AddDirectorToMovieVariablesBuilder {
+  AddDirectorToMovieVariablesPersonId? personId;
+  String? movieId;
+
+  FirebaseDataConnect dataConnect;
 
+  AddDirectorToMovieVariablesBuilder(
+    this.dataConnect, {
+    AddDirectorToMovieVariablesPersonId? this.personId,
+    String? this.movieId,
+  });
   Deserializer<AddDirectorToMovieData> dataDeserializer = (String json) =>
       AddDirectorToMovieData.fromJson(jsonDecode(json) as Map<String, dynamic>);
   Serializer<AddDirectorToMovieVariables> varsSerializer =
       (AddDirectorToMovieVariables vars) => jsonEncode(vars.toJson());
-  MutationRef<AddDirectorToMovieData, AddDirectorToMovieVariables> ref({
-    AddDirectorToMovieVariablesPersonId? personId,
-    String? movieId,
-  }) {
+  MutationRef<AddDirectorToMovieData, AddDirectorToMovieVariables> build() {
     AddDirectorToMovieVariables vars = AddDirectorToMovieVariables(
       personId: personId,
       movieId: movieId,
     );
 
     return dataConnect.mutation(
-        this.name, dataDeserializer, varsSerializer, vars);
+        "addDirectorToMovie", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class AddDirectorToMovie {
+  String name = "addDirectorToMovie";
+  AddDirectorToMovie({required this.dataConnect});
+  AddDirectorToMovieVariablesBuilder ref({
+    AddDirectorToMovieVariablesPersonId? personId,
+    String? movieId,
+  }) {
+    return AddDirectorToMovieVariablesBuilder(
+      dataConnect,
+      personId: personId,
+      movieId: movieId,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -29,6 +48,7 @@ class AddDirectorToMovieDirectedByInsert {
 
   String movieId;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddDirectorToMovieDirectedByInsert.fromJson(Map<String, dynamic> json)
       : directedbyId = nativeFromJson<String>(json['directedbyId']),
         movieId = nativeFromJson<String>(json['movieId']) {}
@@ -46,14 +66,13 @@ class AddDirectorToMovieDirectedByInsert {
   AddDirectorToMovieDirectedByInsert({
     required this.directedbyId,
     required this.movieId,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddDirectorToMovieData {
   AddDirectorToMovieDirectedByInsert directedBy_insert;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddDirectorToMovieData.fromJson(Map<String, dynamic> json)
       : directedBy_insert = AddDirectorToMovieDirectedByInsert.fromJson(
             json['directedBy_insert']) {}
@@ -68,14 +87,13 @@ class AddDirectorToMovieData {
 
   AddDirectorToMovieData({
     required this.directedBy_insert,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddDirectorToMovieVariablesPersonId {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddDirectorToMovieVariablesPersonId.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -89,9 +107,7 @@ class AddDirectorToMovieVariablesPersonId {
 
   AddDirectorToMovieVariablesPersonId({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddDirectorToMovieVariables {
@@ -99,6 +115,7 @@ class AddDirectorToMovieVariables {
 
   String? movieId;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddDirectorToMovieVariables.fromJson(Map<String, dynamic> json) {
     personId = json['personId'] == null
         ? null
@@ -126,7 +143,5 @@ class AddDirectorToMovieVariables {
   AddDirectorToMovieVariables({
     this.personId,
     this.movieId,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_person.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_person.dart
index 7b0aa0466880..a708608d0272 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_person.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_person.dart
@@ -1,22 +1,38 @@
 part of movies;
 
-class AddPerson {
-  String name = "addPerson";
-  AddPerson({required this.dataConnect});
+class AddPersonVariablesBuilder {
+  String? name;
+
+  FirebaseDataConnect dataConnect;
 
+  AddPersonVariablesBuilder(
+    this.dataConnect, {
+    String? this.name,
+  });
   Deserializer<AddPersonData> dataDeserializer = (String json) =>
       AddPersonData.fromJson(jsonDecode(json) as Map<String, dynamic>);
   Serializer<AddPersonVariables> varsSerializer =
       (AddPersonVariables vars) => jsonEncode(vars.toJson());
-  MutationRef<AddPersonData, AddPersonVariables> ref({
-    String? name,
-  }) {
+  MutationRef<AddPersonData, AddPersonVariables> build() {
     AddPersonVariables vars = AddPersonVariables(
       name: name,
     );
 
     return dataConnect.mutation(
-        this.name, dataDeserializer, varsSerializer, vars);
+        "addPerson", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class AddPerson {
+  String name = "addPerson";
+  AddPerson({required this.dataConnect});
+  AddPersonVariablesBuilder ref({
+    String? name,
+  }) {
+    return AddPersonVariablesBuilder(
+      dataConnect,
+      name: name,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -25,6 +41,7 @@ class AddPerson {
 class AddPersonPersonInsert {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddPersonPersonInsert.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -38,14 +55,13 @@ class AddPersonPersonInsert {
 
   AddPersonPersonInsert({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddPersonData {
   AddPersonPersonInsert person_insert;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddPersonData.fromJson(Map<String, dynamic> json)
       : person_insert = AddPersonPersonInsert.fromJson(json['person_insert']) {}
 
@@ -59,14 +75,13 @@ class AddPersonData {
 
   AddPersonData({
     required this.person_insert,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddPersonVariables {
   String? name;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddPersonVariables.fromJson(Map<String, dynamic> json) {
     name = json['name'] == null ? null : nativeFromJson<String>(json['name']);
   }
@@ -83,7 +98,5 @@ class AddPersonVariables {
 
   AddPersonVariables({
     this.name,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_timestamp.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_timestamp.dart
index b31afbd90d3d..d7eac8014552 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_timestamp.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/add_timestamp.dart
@@ -1,22 +1,38 @@
 part of movies;
 
-class AddTimestamp {
-  String name = "addTimestamp";
-  AddTimestamp({required this.dataConnect});
+class AddTimestampVariablesBuilder {
+  Timestamp timestamp;
+
+  FirebaseDataConnect dataConnect;
 
+  AddTimestampVariablesBuilder(
+    this.dataConnect, {
+    required Timestamp this.timestamp,
+  });
   Deserializer<AddTimestampData> dataDeserializer = (String json) =>
       AddTimestampData.fromJson(jsonDecode(json) as Map<String, dynamic>);
   Serializer<AddTimestampVariables> varsSerializer =
       (AddTimestampVariables vars) => jsonEncode(vars.toJson());
-  MutationRef<AddTimestampData, AddTimestampVariables> ref({
-    required Timestamp timestamp,
-  }) {
+  MutationRef<AddTimestampData, AddTimestampVariables> build() {
     AddTimestampVariables vars = AddTimestampVariables(
       timestamp: timestamp,
     );
 
     return dataConnect.mutation(
-        this.name, dataDeserializer, varsSerializer, vars);
+        "addTimestamp", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class AddTimestamp {
+  String name = "addTimestamp";
+  AddTimestamp({required this.dataConnect});
+  AddTimestampVariablesBuilder ref({
+    required Timestamp timestamp,
+  }) {
+    return AddTimestampVariablesBuilder(
+      dataConnect,
+      timestamp: timestamp,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -25,6 +41,7 @@ class AddTimestamp {
 class AddTimestampTimestampHolderInsert {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddTimestampTimestampHolderInsert.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -38,14 +55,13 @@ class AddTimestampTimestampHolderInsert {
 
   AddTimestampTimestampHolderInsert({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddTimestampData {
   AddTimestampTimestampHolderInsert timestampHolder_insert;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddTimestampData.fromJson(Map<String, dynamic> json)
       : timestampHolder_insert = AddTimestampTimestampHolderInsert.fromJson(
             json['timestampHolder_insert']) {}
@@ -60,14 +76,13 @@ class AddTimestampData {
 
   AddTimestampData({
     required this.timestampHolder_insert,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class AddTimestampVariables {
   Timestamp timestamp;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   AddTimestampVariables.fromJson(Map<String, dynamic> json)
       : timestamp = Timestamp.fromJson(json['timestamp']) {}
 
@@ -81,7 +96,5 @@ class AddTimestampVariables {
 
   AddTimestampVariables({
     required this.timestamp,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/create_movie.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/create_movie.dart
index e65aa02bd77d..1c19e2c8029f 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/create_movie.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/create_movie.dart
@@ -1,30 +1,58 @@
 part of movies;
 
-class CreateMovie {
-  String name = "createMovie";
-  CreateMovie({required this.dataConnect});
+class CreateMovieVariablesBuilder {
+  String title;
+  int releaseYear;
+  String genre;
+  double? rating;
+  String? description;
 
+  FirebaseDataConnect dataConnect;
+
+  CreateMovieVariablesBuilder(
+    this.dataConnect, {
+    required String this.title,
+    required int this.releaseYear,
+    required String this.genre,
+    double? this.rating,
+    String? this.description,
+  });
   Deserializer<CreateMovieData> dataDeserializer = (String json) =>
       CreateMovieData.fromJson(jsonDecode(json) as Map<String, dynamic>);
   Serializer<CreateMovieVariables> varsSerializer =
       (CreateMovieVariables vars) => jsonEncode(vars.toJson());
-  MutationRef<CreateMovieData, CreateMovieVariables> ref({
+  MutationRef<CreateMovieData, CreateMovieVariables> build() {
+    CreateMovieVariables vars = CreateMovieVariables(
+      title: title,
+      releaseYear: releaseYear,
+      genre: genre,
+      rating: rating,
+      description: description,
+    );
+
+    return dataConnect.mutation(
+        "createMovie", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class CreateMovie {
+  String name = "createMovie";
+  CreateMovie({required this.dataConnect});
+  CreateMovieVariablesBuilder ref({
     required String title,
     required int releaseYear,
     required String genre,
     double? rating,
     String? description,
   }) {
-    CreateMovieVariables vars = CreateMovieVariables(
+    return CreateMovieVariablesBuilder(
+      dataConnect,
       title: title,
       releaseYear: releaseYear,
       genre: genre,
       rating: rating,
       description: description,
     );
-
-    return dataConnect.mutation(
-        this.name, dataDeserializer, varsSerializer, vars);
   }
 
   FirebaseDataConnect dataConnect;
@@ -33,6 +61,7 @@ class CreateMovie {
 class CreateMovieMovieInsert {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   CreateMovieMovieInsert.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -46,14 +75,13 @@ class CreateMovieMovieInsert {
 
   CreateMovieMovieInsert({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class CreateMovieData {
   CreateMovieMovieInsert movie_insert;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   CreateMovieData.fromJson(Map<String, dynamic> json)
       : movie_insert = CreateMovieMovieInsert.fromJson(json['movie_insert']) {}
 
@@ -67,9 +95,7 @@ class CreateMovieData {
 
   CreateMovieData({
     required this.movie_insert,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class CreateMovieVariables {
@@ -83,6 +109,7 @@ class CreateMovieVariables {
 
   String? description;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   CreateMovieVariables.fromJson(Map<String, dynamic> json)
       : title = nativeFromJson<String>(json['title']),
         releaseYear = nativeFromJson<int>(json['releaseYear']),
@@ -121,7 +148,5 @@ class CreateMovieVariables {
     required this.genre,
     this.rating,
     this.description,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/delete_movie.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/delete_movie.dart
index 82868746cf39..d32c11b2f6fc 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/delete_movie.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/delete_movie.dart
@@ -1,22 +1,38 @@
 part of movies;
 
-class DeleteMovie {
-  String name = "deleteMovie";
-  DeleteMovie({required this.dataConnect});
+class DeleteMovieVariablesBuilder {
+  String id;
+
+  FirebaseDataConnect dataConnect;
 
+  DeleteMovieVariablesBuilder(
+    this.dataConnect, {
+    required String this.id,
+  });
   Deserializer<DeleteMovieData> dataDeserializer = (String json) =>
       DeleteMovieData.fromJson(jsonDecode(json) as Map<String, dynamic>);
   Serializer<DeleteMovieVariables> varsSerializer =
       (DeleteMovieVariables vars) => jsonEncode(vars.toJson());
-  MutationRef<DeleteMovieData, DeleteMovieVariables> ref({
-    required String id,
-  }) {
+  MutationRef<DeleteMovieData, DeleteMovieVariables> build() {
     DeleteMovieVariables vars = DeleteMovieVariables(
       id: id,
     );
 
     return dataConnect.mutation(
-        this.name, dataDeserializer, varsSerializer, vars);
+        "deleteMovie", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class DeleteMovie {
+  String name = "deleteMovie";
+  DeleteMovie({required this.dataConnect});
+  DeleteMovieVariablesBuilder ref({
+    required String id,
+  }) {
+    return DeleteMovieVariablesBuilder(
+      dataConnect,
+      id: id,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -25,6 +41,7 @@ class DeleteMovie {
 class DeleteMovieMovieDelete {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   DeleteMovieMovieDelete.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -38,14 +55,13 @@ class DeleteMovieMovieDelete {
 
   DeleteMovieMovieDelete({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class DeleteMovieData {
   DeleteMovieMovieDelete? movie_delete;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   DeleteMovieData.fromJson(Map<String, dynamic> json) {
     movie_delete = json['movie_delete'] == null
         ? null
@@ -64,14 +80,13 @@ class DeleteMovieData {
 
   DeleteMovieData({
     this.movie_delete,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class DeleteMovieVariables {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   DeleteMovieVariables.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -85,7 +100,5 @@ class DeleteMovieVariables {
 
   DeleteMovieVariables({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies.dart
index 7e80bf8b4fb5..15227ec89c15 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies.dart
@@ -1,15 +1,27 @@
 part of movies;
 
-class ListMovies {
-  String name = "ListMovies";
-  ListMovies({required this.dataConnect});
+class ListMoviesVariablesBuilder {
+  FirebaseDataConnect dataConnect;
 
+  ListMoviesVariablesBuilder(
+    this.dataConnect,
+  );
   Deserializer<ListMoviesData> dataDeserializer = (String json) =>
       ListMoviesData.fromJson(jsonDecode(json) as Map<String, dynamic>);
 
-  QueryRef<ListMoviesData, void> ref() {
+  QueryRef<ListMoviesData, void> build() {
     return dataConnect.query(
-        this.name, dataDeserializer, emptySerializer, null);
+        "ListMovies", dataDeserializer, emptySerializer, null);
+  }
+}
+
+class ListMovies {
+  String name = "ListMovies";
+  ListMovies({required this.dataConnect});
+  ListMoviesVariablesBuilder ref() {
+    return ListMoviesVariablesBuilder(
+      dataConnect,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -22,12 +34,18 @@ class ListMoviesMovies {
 
   List<ListMoviesMoviesDirectedBy> directed_by;
 
+  double? rating;
+
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListMoviesMovies.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']),
         title = nativeFromJson<String>(json['title']),
         directed_by = (json['directed_by'] as List<dynamic>)
             .map((e) => ListMoviesMoviesDirectedBy.fromJson(e))
-            .toList() {}
+            .toList() {
+    rating =
+        json['rating'] == null ? null : nativeFromJson<double>(json['rating']);
+  }
 
   Map<String, dynamic> toJson() {
     Map<String, dynamic> json = {};
@@ -38,6 +56,10 @@ class ListMoviesMovies {
 
     json['directed_by'] = directed_by.map((e) => e.toJson()).toList();
 
+    if (rating != null) {
+      json['rating'] = nativeToJson<double?>(rating);
+    }
+
     return json;
   }
 
@@ -45,14 +67,14 @@ class ListMoviesMovies {
     required this.id,
     required this.title,
     required this.directed_by,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+    this.rating,
+  });
 }
 
 class ListMoviesMoviesDirectedBy {
   String name;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListMoviesMoviesDirectedBy.fromJson(Map<String, dynamic> json)
       : name = nativeFromJson<String>(json['name']) {}
 
@@ -66,14 +88,13 @@ class ListMoviesMoviesDirectedBy {
 
   ListMoviesMoviesDirectedBy({
     required this.name,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class ListMoviesData {
   List<ListMoviesMovies> movies;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListMoviesData.fromJson(Map<String, dynamic> json)
       : movies = (json['movies'] as List<dynamic>)
             .map((e) => ListMoviesMovies.fromJson(e))
@@ -89,7 +110,5 @@ class ListMoviesData {
 
   ListMoviesData({
     required this.movies,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies_by_partial_title.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies_by_partial_title.dart
index a2bb639cb598..768647356638 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies_by_partial_title.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_movies_by_partial_title.dart
@@ -1,23 +1,40 @@
 part of movies;
 
-class ListMoviesByPartialTitle {
-  String name = "ListMoviesByPartialTitle";
-  ListMoviesByPartialTitle({required this.dataConnect});
+class ListMoviesByPartialTitleVariablesBuilder {
+  String input;
+
+  FirebaseDataConnect dataConnect;
 
+  ListMoviesByPartialTitleVariablesBuilder(
+    this.dataConnect, {
+    required String this.input,
+  });
   Deserializer<ListMoviesByPartialTitleData> dataDeserializer = (String json) =>
       ListMoviesByPartialTitleData.fromJson(
           jsonDecode(json) as Map<String, dynamic>);
   Serializer<ListMoviesByPartialTitleVariables> varsSerializer =
       (ListMoviesByPartialTitleVariables vars) => jsonEncode(vars.toJson());
   QueryRef<ListMoviesByPartialTitleData, ListMoviesByPartialTitleVariables>
-      ref({
-    required String input,
-  }) {
+      build() {
     ListMoviesByPartialTitleVariables vars = ListMoviesByPartialTitleVariables(
       input: input,
     );
 
-    return dataConnect.query(this.name, dataDeserializer, varsSerializer, vars);
+    return dataConnect.query(
+        "ListMoviesByPartialTitle", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class ListMoviesByPartialTitle {
+  String name = "ListMoviesByPartialTitle";
+  ListMoviesByPartialTitle({required this.dataConnect});
+  ListMoviesByPartialTitleVariablesBuilder ref({
+    required String input,
+  }) {
+    return ListMoviesByPartialTitleVariablesBuilder(
+      dataConnect,
+      input: input,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -32,6 +49,7 @@ class ListMoviesByPartialTitleMovies {
 
   double? rating;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListMoviesByPartialTitleMovies.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']),
         title = nativeFromJson<String>(json['title']),
@@ -61,14 +79,13 @@ class ListMoviesByPartialTitleMovies {
     required this.title,
     required this.genre,
     this.rating,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class ListMoviesByPartialTitleData {
   List<ListMoviesByPartialTitleMovies> movies;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListMoviesByPartialTitleData.fromJson(Map<String, dynamic> json)
       : movies = (json['movies'] as List<dynamic>)
             .map((e) => ListMoviesByPartialTitleMovies.fromJson(e))
@@ -84,14 +101,13 @@ class ListMoviesByPartialTitleData {
 
   ListMoviesByPartialTitleData({
     required this.movies,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class ListMoviesByPartialTitleVariables {
   String input;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListMoviesByPartialTitleVariables.fromJson(Map<String, dynamic> json)
       : input = nativeFromJson<String>(json['input']) {}
 
@@ -105,7 +121,5 @@ class ListMoviesByPartialTitleVariables {
 
   ListMoviesByPartialTitleVariables({
     required this.input,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_persons.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_persons.dart
index 3e8c215e275c..85c7a33a124c 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_persons.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_persons.dart
@@ -1,15 +1,27 @@
 part of movies;
 
-class ListPersons {
-  String name = "ListPersons";
-  ListPersons({required this.dataConnect});
+class ListPersonsVariablesBuilder {
+  FirebaseDataConnect dataConnect;
 
+  ListPersonsVariablesBuilder(
+    this.dataConnect,
+  );
   Deserializer<ListPersonsData> dataDeserializer = (String json) =>
       ListPersonsData.fromJson(jsonDecode(json) as Map<String, dynamic>);
 
-  QueryRef<ListPersonsData, void> ref() {
+  QueryRef<ListPersonsData, void> build() {
     return dataConnect.query(
-        this.name, dataDeserializer, emptySerializer, null);
+        "ListPersons", dataDeserializer, emptySerializer, null);
+  }
+}
+
+class ListPersons {
+  String name = "ListPersons";
+  ListPersons({required this.dataConnect});
+  ListPersonsVariablesBuilder ref() {
+    return ListPersonsVariablesBuilder(
+      dataConnect,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -20,6 +32,7 @@ class ListPersonsPeople {
 
   String name;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListPersonsPeople.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']),
         name = nativeFromJson<String>(json['name']) {}
@@ -37,14 +50,13 @@ class ListPersonsPeople {
   ListPersonsPeople({
     required this.id,
     required this.name,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class ListPersonsData {
   List<ListPersonsPeople> people;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListPersonsData.fromJson(Map<String, dynamic> json)
       : people = (json['people'] as List<dynamic>)
             .map((e) => ListPersonsPeople.fromJson(e))
@@ -60,7 +72,5 @@ class ListPersonsData {
 
   ListPersonsData({
     required this.people,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_thing.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_thing.dart
index 3fc1e36ac41c..d5439fba8c13 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_thing.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_thing.dart
@@ -1,21 +1,38 @@
 part of movies;
 
-class ListThing {
-  String name = "ListThing";
-  ListThing({required this.dataConnect});
+class ListThingVariablesBuilder {
+  AnyValue? data;
+
+  FirebaseDataConnect dataConnect;
 
+  ListThingVariablesBuilder(
+    this.dataConnect, {
+    AnyValue? this.data,
+  });
   Deserializer<ListThingData> dataDeserializer = (String json) =>
       ListThingData.fromJson(jsonDecode(json) as Map<String, dynamic>);
   Serializer<ListThingVariables> varsSerializer =
       (ListThingVariables vars) => jsonEncode(vars.toJson());
-  QueryRef<ListThingData, ListThingVariables> ref({
-    dynamic? data,
-  }) {
+  QueryRef<ListThingData, ListThingVariables> build() {
     ListThingVariables vars = ListThingVariables(
-      data: AnyValue(data),
+      data: data,
     );
 
-    return dataConnect.query(this.name, dataDeserializer, varsSerializer, vars);
+    return dataConnect.query(
+        "ListThing", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class ListThing {
+  String name = "ListThing";
+  ListThing({required this.dataConnect});
+  ListThingVariablesBuilder ref({
+    dynamic? data,
+  }) {
+    return ListThingVariablesBuilder(
+      dataConnect,
+      data: data,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -24,6 +41,7 @@ class ListThing {
 class ListThingThings {
   AnyValue title;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListThingThings.fromJson(Map<String, dynamic> json)
       : title = AnyValue.fromJson(json['title']) {}
 
@@ -37,14 +55,13 @@ class ListThingThings {
 
   ListThingThings({
     required this.title,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-  }
+  });
 }
 
 class ListThingData {
   List<ListThingThings> things;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListThingData.fromJson(Map<String, dynamic> json)
       : things = (json['things'] as List<dynamic>)
             .map((e) => ListThingThings.fromJson(e))
@@ -60,14 +77,13 @@ class ListThingData {
 
   ListThingData({
     required this.things,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-  }
+  });
 }
 
 class ListThingVariables {
   AnyValue? data;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListThingVariables.fromJson(Map<String, dynamic> json) {
     data = json['data'] == null ? null : AnyValue.fromJson(json['data']);
   }
@@ -84,7 +100,5 @@ class ListThingVariables {
 
   ListThingVariables({
     this.data,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_timestamps.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_timestamps.dart
index b7a167a4973e..3ad8465bee61 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_timestamps.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/list_timestamps.dart
@@ -1,15 +1,27 @@
 part of movies;
 
-class ListTimestamps {
-  String name = "ListTimestamps";
-  ListTimestamps({required this.dataConnect});
+class ListTimestampsVariablesBuilder {
+  FirebaseDataConnect dataConnect;
 
+  ListTimestampsVariablesBuilder(
+    this.dataConnect,
+  );
   Deserializer<ListTimestampsData> dataDeserializer = (String json) =>
       ListTimestampsData.fromJson(jsonDecode(json) as Map<String, dynamic>);
 
-  QueryRef<ListTimestampsData, void> ref() {
+  QueryRef<ListTimestampsData, void> build() {
     return dataConnect.query(
-        this.name, dataDeserializer, emptySerializer, null);
+        "ListTimestamps", dataDeserializer, emptySerializer, null);
+  }
+}
+
+class ListTimestamps {
+  String name = "ListTimestamps";
+  ListTimestamps({required this.dataConnect});
+  ListTimestampsVariablesBuilder ref() {
+    return ListTimestampsVariablesBuilder(
+      dataConnect,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -20,6 +32,7 @@ class ListTimestampsTimestampHolders {
 
   DateTime? date;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListTimestampsTimestampHolders.fromJson(Map<String, dynamic> json)
       : timestamp = Timestamp.fromJson(json['timestamp']) {
     date = json['date'] == null ? null : nativeFromJson<DateTime>(json['date']);
@@ -40,14 +53,13 @@ class ListTimestampsTimestampHolders {
   ListTimestampsTimestampHolders({
     required this.timestamp,
     this.date,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class ListTimestampsData {
   List<ListTimestampsTimestampHolders> timestampHolders;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ListTimestampsData.fromJson(Map<String, dynamic> json)
       : timestampHolders = (json['timestampHolders'] as List<dynamic>)
             .map((e) => ListTimestampsTimestampHolders.fromJson(e))
@@ -63,7 +75,5 @@ class ListTimestampsData {
 
   ListTimestampsData({
     required this.timestampHolders,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/movies.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/movies.dart
index 2ddd9a5ce9a3..c85f61434f19 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/movies.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/movies.dart
@@ -3,14 +3,6 @@ library movies;
 import 'package:firebase_data_connect/firebase_data_connect.dart';
 import 'dart:convert';
 
-part 'list_movies.dart';
-
-part 'list_movies_by_partial_title.dart';
-
-part 'list_persons.dart';
-
-part 'list_thing.dart';
-
 part 'add_person.dart';
 
 part 'add_director_to_movie.dart';
@@ -29,25 +21,17 @@ part 'thing.dart';
 
 part 'seed_data.dart';
 
-part 'list_timestamps.dart';
+part 'list_movies.dart';
 
-class MoviesConnector {
-  ListMovies get listMovies {
-    return ListMovies(dataConnect: dataConnect);
-  }
+part 'list_movies_by_partial_title.dart';
 
-  ListMoviesByPartialTitle get listMoviesByPartialTitle {
-    return ListMoviesByPartialTitle(dataConnect: dataConnect);
-  }
+part 'list_persons.dart';
 
-  ListPersons get listPersons {
-    return ListPersons(dataConnect: dataConnect);
-  }
+part 'list_thing.dart';
 
-  ListThing get listThing {
-    return ListThing(dataConnect: dataConnect);
-  }
+part 'list_timestamps.dart';
 
+class MoviesConnector {
   AddPerson get addPerson {
     return AddPerson(dataConnect: dataConnect);
   }
@@ -84,6 +68,22 @@ class MoviesConnector {
     return SeedData(dataConnect: dataConnect);
   }
 
+  ListMovies get listMovies {
+    return ListMovies(dataConnect: dataConnect);
+  }
+
+  ListMoviesByPartialTitle get listMoviesByPartialTitle {
+    return ListMoviesByPartialTitle(dataConnect: dataConnect);
+  }
+
+  ListPersons get listPersons {
+    return ListPersons(dataConnect: dataConnect);
+  }
+
+  ListThing get listThing {
+    return ListThing(dataConnect: dataConnect);
+  }
+
   ListTimestamps get listTimestamps {
     return ListTimestamps(dataConnect: dataConnect);
   }
@@ -97,8 +97,9 @@ class MoviesConnector {
   MoviesConnector({required this.dataConnect});
   static MoviesConnector get instance {
     return MoviesConnector(
-        dataConnect:
-            FirebaseDataConnect.instanceFor(connectorConfig: connectorConfig));
+        dataConnect: FirebaseDataConnect.instanceFor(
+            connectorConfig: connectorConfig,
+            sdkType: CallerSDKType.generated));
   }
 
   FirebaseDataConnect dataConnect;
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_data.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_data.dart
index acb7ceb55da1..a8febef0e604 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_data.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_data.dart
@@ -1,15 +1,27 @@
 part of movies;
 
-class SeedData {
-  String name = "seedData";
-  SeedData({required this.dataConnect});
+class SeedDataVariablesBuilder {
+  FirebaseDataConnect dataConnect;
 
+  SeedDataVariablesBuilder(
+    this.dataConnect,
+  );
   Deserializer<SeedDataData> dataDeserializer = (String json) =>
       SeedDataData.fromJson(jsonDecode(json) as Map<String, dynamic>);
 
-  MutationRef<SeedDataData, void> ref() {
+  MutationRef<SeedDataData, void> build() {
     return dataConnect.mutation(
-        this.name, dataDeserializer, emptySerializer, null);
+        "seedData", dataDeserializer, emptySerializer, null);
+  }
+}
+
+class SeedData {
+  String name = "seedData";
+  SeedData({required this.dataConnect});
+  SeedDataVariablesBuilder ref() {
+    return SeedDataVariablesBuilder(
+      dataConnect,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -18,6 +30,7 @@ class SeedData {
 class SeedDataTheMatrix {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   SeedDataTheMatrix.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -31,14 +44,13 @@ class SeedDataTheMatrix {
 
   SeedDataTheMatrix({
     required this.id,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-  }
+  });
 }
 
 class SeedDataData {
   SeedDataTheMatrix the_matrix;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   SeedDataData.fromJson(Map<String, dynamic> json)
       : the_matrix = SeedDataTheMatrix.fromJson(json['the_matrix']) {}
 
@@ -52,7 +64,5 @@ class SeedDataData {
 
   SeedDataData({
     required this.the_matrix,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_movies.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_movies.dart
index 45a39edc6297..52465d236d6c 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_movies.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/seed_movies.dart
@@ -1,15 +1,27 @@
 part of movies;
 
-class SeedMovies {
-  String name = "seedMovies";
-  SeedMovies({required this.dataConnect});
+class SeedMoviesVariablesBuilder {
+  FirebaseDataConnect dataConnect;
 
+  SeedMoviesVariablesBuilder(
+    this.dataConnect,
+  );
   Deserializer<SeedMoviesData> dataDeserializer = (String json) =>
       SeedMoviesData.fromJson(jsonDecode(json) as Map<String, dynamic>);
 
-  MutationRef<SeedMoviesData, void> ref() {
+  MutationRef<SeedMoviesData, void> build() {
     return dataConnect.mutation(
-        this.name, dataDeserializer, emptySerializer, null);
+        "seedMovies", dataDeserializer, emptySerializer, null);
+  }
+}
+
+class SeedMovies {
+  String name = "seedMovies";
+  SeedMovies({required this.dataConnect});
+  SeedMoviesVariablesBuilder ref() {
+    return SeedMoviesVariablesBuilder(
+      dataConnect,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -18,6 +30,7 @@ class SeedMovies {
 class SeedMoviesTheMatrix {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   SeedMoviesTheMatrix.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -31,14 +44,13 @@ class SeedMoviesTheMatrix {
 
   SeedMoviesTheMatrix({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class SeedMoviesJurassicPark {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   SeedMoviesJurassicPark.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -52,9 +64,7 @@ class SeedMoviesJurassicPark {
 
   SeedMoviesJurassicPark({
     required this.id,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
 
 class SeedMoviesData {
@@ -62,6 +72,7 @@ class SeedMoviesData {
 
   SeedMoviesJurassicPark jurassic_park;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   SeedMoviesData.fromJson(Map<String, dynamic> json)
       : the_matrix = SeedMoviesTheMatrix.fromJson(json['the_matrix']),
         jurassic_park =
@@ -80,7 +91,5 @@ class SeedMoviesData {
   SeedMoviesData({
     required this.the_matrix,
     required this.jurassic_park,
-  }) {
-    // TODO: Only show this if there are optional fields.
-  }
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/thing.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/thing.dart
index 979d8b23049e..a9baaa19394a 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/thing.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/generated/thing.dart
@@ -1,22 +1,39 @@
 part of movies;
 
-class Thing {
-  String name = "thing";
-  Thing({required this.dataConnect});
+class ThingVariablesBuilder {
+  Optional<AnyValue> _title =
+      Optional.optional(AnyValue.fromJson, defaultSerializer);
 
+  FirebaseDataConnect dataConnect;
+  ThingVariablesBuilder title(AnyValue t) {
+    this._title.value = t;
+    return this;
+  }
+
+  ThingVariablesBuilder(
+    this.dataConnect,
+  );
   Deserializer<ThingData> dataDeserializer = (String json) =>
       ThingData.fromJson(jsonDecode(json) as Map<String, dynamic>);
   Serializer<ThingVariables> varsSerializer =
       (ThingVariables vars) => jsonEncode(vars.toJson());
-  MutationRef<ThingData, ThingVariables> ref({
-    dynamic title,
-  }) {
+  MutationRef<ThingData, ThingVariables> build() {
     ThingVariables vars = ThingVariables(
-      title: AnyValue(title),
+      title: _title,
     );
 
     return dataConnect.mutation(
-        this.name, dataDeserializer, varsSerializer, vars);
+        "thing", dataDeserializer, varsSerializer, vars);
+  }
+}
+
+class Thing {
+  String name = "thing";
+  Thing({required this.dataConnect});
+  ThingVariablesBuilder ref() {
+    return ThingVariablesBuilder(
+      dataConnect,
+    );
   }
 
   FirebaseDataConnect dataConnect;
@@ -25,6 +42,7 @@ class Thing {
 class ThingThingInsert {
   String id;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ThingThingInsert.fromJson(Map<String, dynamic> json)
       : id = nativeFromJson<String>(json['id']) {}
 
@@ -38,14 +56,13 @@ class ThingThingInsert {
 
   ThingThingInsert({
     required this.id,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-  }
+  });
 }
 
 class ThingData {
   ThingThingInsert thing_insert;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ThingData.fromJson(Map<String, dynamic> json)
       : thing_insert = ThingThingInsert.fromJson(json['thing_insert']) {}
 
@@ -59,42 +76,29 @@ class ThingData {
 
   ThingData({
     required this.thing_insert,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-  }
+  });
 }
 
 class ThingVariables {
-  Optional<AnyValue> _title =
-      Optional.optional(AnyValue.fromJson, defaultSerializer);
-
-  set title(AnyValue t) {
-    this._title.value = t;
-  }
-
-  AnyValue get title => this._title.value!;
+  late Optional<AnyValue> title;
 
+  // TODO(mtewani): Check what happens when an optional field is retrieved from json.
   ThingVariables.fromJson(Map<String, dynamic> json) {
-    _title.value =
+    title.value =
         json['title'] == null ? null : AnyValue.fromJson(json['title']);
   }
 
   Map<String, dynamic> toJson() {
     Map<String, dynamic> json = {};
 
-    if (_title.state == OptionalState.set) {
-      json['title'] = _title.toJson();
+    if (title.state == OptionalState.set) {
+      json['title'] = title.toJson();
     }
 
     return json;
   }
 
   ThingVariables({
-    AnyValue? title,
-  }) {
-    // TODO(mtewani): Only show this if there are optional fields.
-
-    this._title = Optional.optional(AnyValue.fromJson, defaultSerializer);
-    this._title.value = title;
-  }
+    required this.title,
+  });
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/example/lib/main.dart b/packages/firebase_data_connect/firebase_data_connect/example/lib/main.dart
index 1faa49a538cf..2fb2d87c64f4 100644
--- a/packages/firebase_data_connect/firebase_data_connect/example/lib/main.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/example/lib/main.dart
@@ -101,7 +101,7 @@ class _DataConnectWidgetState extends State<DataConnectWidget> {
   double _rating = 0;
 
   Future<void> triggerReload() async {
-    QueryRef ref = MoviesConnector.instance.listMovies.ref();
+    QueryRef ref = MoviesConnector.instance.listMovies.ref().build();
     ref.execute();
   }
 
@@ -110,7 +110,7 @@ class _DataConnectWidgetState extends State<DataConnectWidget> {
     super.initState();
 
     QueryRef<ListMoviesData, void> ref =
-        MoviesConnector.instance.listMovies.ref();
+        MoviesConnector.instance.listMovies.ref().build();
 
     ref.subscribe().listen((event) {
       setState(() {
@@ -185,12 +185,14 @@ class _DataConnectWidgetState extends State<DataConnectWidget> {
                 return;
               }
 
-              MutationRef ref = MoviesConnector.instance.createMovie.ref(
-                title: title,
-                releaseYear: _releaseYearDate.year,
-                genre: genre,
-                rating: _rating,
-              );
+              MutationRef ref = MoviesConnector.instance.createMovie
+                  .ref(
+                    title: title,
+                    releaseYear: _releaseYearDate.year,
+                    genre: genre,
+                    rating: _rating,
+                  )
+                  .build();
               try {
                 await ref.execute();
                 triggerReload();
diff --git a/packages/firebase_data_connect/firebase_data_connect/lib/src/optional.dart b/packages/firebase_data_connect/firebase_data_connect/lib/src/optional.dart
index 400be831cfb2..9d69a4040849 100644
--- a/packages/firebase_data_connect/firebase_data_connect/lib/src/optional.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/lib/src/optional.dart
@@ -76,13 +76,18 @@ dynamic nativeToJson<T>(T type) {
   throw UnimplementedError('This type is unimplemented: ${type.runtimeType}');
 }
 
-T nativeFromJson<T>(String json) {
-  if (T == bool) return (json.toLowerCase() == 'true') as T;
-  if (T == int) return int.parse(json) as T;
-  if (T == double) return double.parse(json) as T;
-  if (T == num) return num.parse(json) as T;
-  if (T == String) return json as T;
-  if (T == DateTime) return DateTime.parse(json) as T;
-
+T nativeFromJson<T>(dynamic input) {
+  if ((input is bool && T == bool) ||
+      (input is int && T == int) ||
+      (input is double && T == double) ||
+      (input is num && input == num)) {
+    return input;
+  } else if (input is String) {
+    if (T == DateTime) {
+      return DateTime.parse(input) as T;
+    } else if (T == String) {
+      return input as T;
+    }
+  }
   throw UnimplementedError('This type is unimplemented: ${T.runtimeType}');
 }
diff --git a/packages/firebase_data_connect/firebase_data_connect/test/src/optional_test.dart b/packages/firebase_data_connect/firebase_data_connect/test/src/optional_test.dart
index 62cd4e02450b..d4aa599c2b43 100644
--- a/packages/firebase_data_connect/firebase_data_connect/test/src/optional_test.dart
+++ b/packages/firebase_data_connect/firebase_data_connect/test/src/optional_test.dart
@@ -74,10 +74,14 @@ void main() {
     });
 
     test('nativeFromJson correctly deserializes primitive types', () {
-      expect(nativeFromJson<int>('42'), equals(42));
-      expect(nativeFromJson<bool>('true'), equals(true));
+      expect(nativeFromJson<String>('42'), equals('42'));
+      expect(nativeFromJson<bool>(true), equals(true));
       expect(nativeFromJson<String>('Test'), equals('Test'));
     });
+    test('nativeFromJson correctly deserializes DateTime strings', () {
+      expect(nativeFromJson<DateTime>('2024-01-01'),
+          equals(DateTime.parse('2024-01-01')));
+    });
 
     test('nativeToJson throws UnimplementedError for unsupported types', () {
       expect(() => nativeToJson(Object()), throwsUnimplementedError);