transient annotation is implemented

example/lib/task.dart

@@ -7,7 +7,10 @@ class Task {
 
   final String message;
 
-  Task(this.id, this.message);
+  @transient
+  String description;
+
+  Task(this.id, this.message, [this.description='']);
 
   @override
   bool operator ==(Object other) =>

floor_annotation/lib/floor_annotation.dart

@@ -12,4 +12,5 @@ export 'src/on_conflict_strategy.dart';
 export 'src/primary_key.dart';
 export 'src/query.dart';
 export 'src/transaction.dart';
+export 'src/transient.dart';
 export 'src/update.dart';

floor_annotation/lib/src/transient.dart

@@ -0,0 +1,7 @@
+/// Marks a field in an [Entity] as the transient.
+class Transient {
+  const Transient();
+}
+
+/// Marks a field in an [Entity] as the transient.
+const transient = Transient();

floor_generator/lib/processor/entity_processor.dart

@@ -30,16 +30,16 @@ class EntityProcessor extends Processor<Entity> {
   @override
   Entity process() {
     final name = _getName();
-    final fields = _getFields();
+    final allFieldsButTransients  = _getAllButTransientsFields();
 
     return Entity(
       _classElement,
       name,
-      fields,
-      _getPrimaryKey(fields),
+      allFieldsButTransients,
+      _getPrimaryKey(allFieldsButTransients),
       _getForeignKeys(),
-      _getIndices(fields, name),
-      _getConstructor(fields),
+      _getIndices(allFieldsButTransients, name),
+      _getConstructor(allFieldsButTransients),
     );
   }
 
@@ -53,9 +53,9 @@ class EntityProcessor extends Processor<Entity> {
   }
 
   @nonNull
-  List<Field> _getFields() {
+  List<Field> _getAllButTransientsFields() {
     return _classElement.fields
-        .where(_isNotHashCode)
+        .where(_isNotHashCode).where(_isNotTransient)
         .map((field) => FieldProcessor(field).process())
         .toList();
   }
@@ -65,6 +65,12 @@ class EntityProcessor extends Processor<Entity> {
     return fieldElement.displayName != 'hashCode';
   }
 
+  @nonNull
+  bool _isNotTransient(final FieldElement fieldElement) {
+    return !typeChecker(annotations.Transient)
+        .hasAnnotationOfExact(fieldElement);
+  }
+
   @nonNull
   List<ForeignKey> _getForeignKeys() {
     return _entityTypeChecker
@@ -231,7 +237,7 @@ class EntityProcessor extends Processor<Entity> {
   @nonNull
   String _getConstructor(final List<Field> fields) {
     final columnNames = fields.map((field) => field.columnName).toList();
-    final constructorParameters = _classElement.constructors.first.parameters;
+    final constructorParameters = _classElement.constructors.first.parameters. where((f)=> columnNames.contains(f.name)).toList();
 
     final parameterValues = <String>[];
 

floor_generator/lib/value_object/transient.dart

@@ -0,0 +1,21 @@
+import 'package:collection/collection.dart';
+import 'package:floor_generator/value_object/field.dart';
+
+/// Transient representation of a field in an Entity
+class Transient {
+  final List<Field> fields;
+
+  Transient(this.fields);
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is Transient &&
+          runtimeType == other.runtimeType &&
+          const ListEquality<Field>().equals(fields, other.fields);
+
+  @override
+  String toString() {
+    return 'Transient{fields: $fields}';
+  }
+}

floor_generator/test/processor/entity_processor_test.dart

@@ -128,6 +128,45 @@ void main() {
       expect(actual, equals(expected));
     });
   });
+
+  test('Should entity with transient field be not equals to floor processed entity', () async {
+     final classElement = await _createClassElement('''
+        @entity
+        class Person {
+        @primaryKey
+        final int id;
+
+        final String name;
+
+        @transient
+        String nickName;
+
+        Person(this.id, this.name, [this.nickName='']);
+        }
+        ''');
+
+    final actual = EntityProcessor(classElement).process();
+
+    const name = 'Person';
+    final fields = classElement.fields
+        .map((fieldElement) => FieldProcessor(fieldElement).process())
+        .toList();
+    final primaryKey = PrimaryKey([fields[0]], false);
+    const foreignKeys = <ForeignKey>[];
+    const indices = <Index>[];
+    const constructor = "Person(row['id'] as int, row['name'] as String)";
+    final expected = Entity(
+      classElement,
+      name,
+      fields,
+      primaryKey,
+      foreignKeys,
+      indices,
+      constructor,
+    );
+
+    expect(actual.fields, isNot(equals(expected.fields)));
+  });
 }
 
 Future<ClassElement> _createClassElement(final String clazz) async {