orm 2.1.0-beta.2

angel_orm/CHANGELOG.md

@@ -1,3 +1,7 @@
+# 2.1.0-beta.2
+* Add `expressions` to `Query`, to support custom SQL expressions that are
+read as normal fields.
+
 # 2.1.0-beta.1
 * Calls to `leftJoin`, etc. alias all fields in a child query, to prevent
 `ambiguous column a0.id` errors.

angel_orm/lib/src/query.dart

@@ -17,6 +17,10 @@ abstract class Query<T, Where extends QueryWhere> extends QueryBase<T> {
   // the parent's context.
   final Query parent;
 
+  /// A map of field names to explicit SQL expressions. The expressions will be aliased
+  /// to the given names.
+  final Map<String, String> expressions = {};
+
   String _crossJoin, _groupBy;
   int _limit, _offset;
 
@@ -36,7 +40,13 @@ abstract class Query<T, Where extends QueryWhere> extends QueryBase<T> {
   QueryValues get values;
 
   /// Preprends the [tableName] to the [String], [s].
-  String adornWithTableName(String s) => '$tableName.$s';
+  String adornWithTableName(String s) {
+    if (expressions.containsKey(s)) {
+      return '(${expressions[s]} AS $s)';
+    } else {
+      return '$tableName.$s';
+    }
+  }
 
   /// Returns a unique version of [name], which will not produce a collision within
   /// the context of this [query].
@@ -233,6 +243,10 @@ abstract class Query<T, Where extends QueryWhere> extends QueryBase<T> {
     } else {
       f = List<String>.from(fields.map((s) {
         var ss = includeTableName ? '$tableName.$s' : s;
+        if (expressions.containsKey(s)) {
+          // ss = '(' + expressions[s] + ')';
+          ss = expressions[s];
+        }
         var cast = casts[s];
         if (cast != null) ss = 'CAST ($ss AS $cast)';
         if (aliases.containsKey(s)) {
@@ -241,6 +255,15 @@ abstract class Query<T, Where extends QueryWhere> extends QueryBase<T> {
           } else {
             ss = '$ss AS ${aliases[s]}';
           }
+          if (expressions.containsKey(s)) {
+            ss = '($ss)';
+          }
+        } else if (expressions.containsKey(s)) {
+          if (cast != null) {
+            ss = '(($ss) AS $s)';
+          } else {
+            ss = '($ss AS $s)';
+          }
         }
         return ss;
       }));

angel_orm/pubspec.yaml

@@ -1,5 +1,5 @@
 name: angel_orm
-version: 2.1.0-beta.1
+version: 2.1.0-beta.2
 description: Runtime support for Angel's ORM. Includes base classes for queries.
 author: Tobe O <thosakwe@gmail.com>
 homepage: https://github.com/angel-dart/orm

angel_orm_generator/lib/src/migration_generator.dart

@@ -82,6 +82,9 @@ class MigrationGenerator extends GeneratorForAnnotation<Orm> {
 
             List<String> dup = [];
             ctx.columns.forEach((name, col) {
+              // Skip custom-expression columns.
+              if (col.hasExpression) return;
+
               var key = ctx.buildContext.resolveFieldName(name);
 
               if (dup.contains(key)) {

angel_orm_generator/lib/src/orm_build_context.dart

@@ -291,6 +291,17 @@ Future<OrmBuildContext> buildOrmContext(
       if (column?.type == null) {
         throw 'Cannot infer SQL column type for field "${ctx.buildContext.originalClassName}.${field.name}" with type "${field.type.displayName}".';
       }
+
+      // Expressions...
+      column = Column(
+        isNullable: column.isNullable,
+        length: column.length,
+        type: column.type,
+        indexType: column.indexType,
+        expression:
+            ConstantReader(columnAnnotation).peek('expression')?.stringValue,
+      );
+
       ctx.columns[field.name] = column;
 
       if (!ctx.effectiveFields.any((f) => f.name == field.name)) {
@@ -372,6 +383,14 @@ class OrmBuildContext {
   final Map<String, RelationshipReader> relations = {};
 
   OrmBuildContext(this.buildContext, this.ormAnnotation, this.tableName);
+
+  bool isNotCustomExprField(FieldElement field) {
+    var col = columns[field.name];
+    return col?.hasExpression != true;
+  }
+
+  Iterable<FieldElement> get effectiveNormalFields =>
+      effectiveFields.where(isNotCustomExprField);
 }
 
 class _ColumnType implements ColumnType {

angel_orm_generator/lib/src/orm_generator.dart

@@ -275,6 +275,16 @@ class OrmGenerator extends GeneratorForAnnotation<Orm> {
               Code('trampoline.add(tableName);'),
             ]);
 
+            // Add any manual SQL expressions.
+            ctx.columns.forEach((name, col) {
+              if (col != null && col.hasExpression) {
+                var lhs = refer('expressions').index(
+                    literalString(ctx.buildContext.resolveFieldName(name)));
+                var rhs = literalString(col.expression);
+                b.addExpression(lhs.assign(rhs));
+              }
+            });
+
             // Add a constructor that initializes _where
             b.addExpression(
               refer('_where')
@@ -499,7 +509,8 @@ class OrmGenerator extends GeneratorForAnnotation<Orm> {
           ..annotations.add(refer('override'))
           ..type = MethodType.getter
           ..body = Block((b) {
-            var references = ctx.effectiveFields.map((f) => refer(f.name));
+            var references =
+                ctx.effectiveNormalFields.map((f) => refer(f.name));
             b.addExpression(literalList(references).returned);
           });
       }));
@@ -507,7 +518,7 @@ class OrmGenerator extends GeneratorForAnnotation<Orm> {
       var initializers = <Code>[];
 
       // Add builders for each field
-      for (var field in ctx.effectiveFields) {
+      for (var field in ctx.effectiveNormalFields) {
         var name = field.name;
         var args = <Expression>[];
         DartType type;
@@ -620,7 +631,7 @@ class OrmGenerator extends GeneratorForAnnotation<Orm> {
       }));
 
       // Each field generates a getter and setter
-      for (var field in ctx.effectiveFields) {
+      for (var field in ctx.effectiveNormalFields) {
         var fType = field.type;
         var name = ctx.buildContext.resolveFieldName(field.name);
         var type = convertTypeReference(field.type);
@@ -684,7 +695,7 @@ class OrmGenerator extends GeneratorForAnnotation<Orm> {
             ..name = 'model'
             ..type = ctx.buildContext.modelClassType))
           ..body = Block((b) {
-            for (var field in ctx.effectiveFields) {
+            for (var field in ctx.effectiveNormalFields) {
               if (isSpecialId(ctx, field) || field is RelationFieldImpl) {
                 continue;
               }
@@ -692,7 +703,7 @@ class OrmGenerator extends GeneratorForAnnotation<Orm> {
                   .assign(refer('model').property(field.name)));
             }
 
-            for (var field in ctx.effectiveFields) {
+            for (var field in ctx.effectiveNormalFields) {
               if (field is RelationFieldImpl) {
                 var original = field.originalFieldName;
                 var prop = refer('model').property(original);

angel_orm_postgres/pubspec.yaml

@@ -15,6 +15,6 @@ dev_dependencies:
     path: ../angel_orm_test
   pretty_logging: ^1.0.0
   test: ^1.0.0
-# dependency_overrides:
-#   angel_orm:
-#     path: ../angel_orm
+dependency_overrides:
+  angel_orm:
+    path: ../angel_orm

angel_orm_postgres/test/all_test.dart

@@ -12,6 +12,8 @@ void main() {
   group('postgresql', () {
     group('belongsTo',
         () => belongsToTests(pg(['author', 'book']), close: closePg));
+    group('customExpr',
+        () => customExprTests(pg(['custom_expr']), close: closePg));
     group(
         'edgeCase',
         () => edgeCaseTests(pg(['unorthodox', 'weird_join', 'song', 'numba']),

angel_orm_postgres/test/migrations/custom_expr.sql

@@ -0,0 +1,13 @@
+CREATE TEMPORARY TABLE "numbers" (
+    id serial PRIMARY KEY,
+    created_at timestamp,
+    updated_at timestamp
+);
+
+CREATE TEMPORARY TABLE "alphabets" (
+    id serial PRIMARY KEY,
+    value TEXT,
+    numbers_id int,
+    created_at timestamp,
+    updated_at timestamp
+);

angel_orm_test/lib/angel_orm_test.dart

@@ -1,4 +1,5 @@
 export 'src/belongs_to_test.dart';
+export 'src/custom_expr_test.dart';
 export 'src/edge_case_test.dart';
 export 'src/enum_and_nested_test.dart';
 export 'src/has_many_test.dart';

angel_orm_test/lib/src/custom_expr_test.dart

@@ -0,0 +1,43 @@
+import 'dart:async';
+import 'package:angel_orm/angel_orm.dart';
+import 'package:test/test.dart';
+import 'models/custom_expr.dart';
+import 'util.dart';
+
+customExprTests(FutureOr<QueryExecutor> Function() createExecutor,
+    {FutureOr<void> Function(QueryExecutor) close}) {
+  QueryExecutor executor;
+  Numbers numbersModel;
+
+  close ??= (_) => null;
+
+  setUp(() async {
+    executor = await createExecutor();
+
+    var now = DateTime.now();
+    var nQuery = NumbersQuery();
+    nQuery.values
+      ..createdAt = now
+      ..updatedAt = now;
+    numbersModel = await nQuery.insert(executor);
+  });
+
+  tearDown(() => close(executor));
+
+  test('fetches correct result', () async {
+    expect(numbersModel.two, 2);
+  });
+
+  test('in relation', () async {
+    var abcQuery = AlphabetQuery();
+    abcQuery.values
+      ..value = 'abc'
+      ..numbersId = numbersModel.idAsInt
+      ..createdAt = numbersModel.createdAt
+      ..updatedAt = numbersModel.updatedAt;
+    var abc = await abcQuery.insert(executor);
+    expect(abc.numbers, numbersModel);
+    expect(abc.numbers.two, 2);
+    expect(abc.value, 'abc');
+  });
+}

angel_orm_test/lib/src/models/custom_expr.dart

@@ -0,0 +1,21 @@
+import 'package:angel_migration/angel_migration.dart';
+import 'package:angel_model/angel_model.dart';
+import 'package:angel_orm/angel_orm.dart';
+import 'package:angel_serialize/angel_serialize.dart';
+part 'custom_expr.g.dart';
+
+@serializable
+@orm
+class _Numbers extends Model {
+  @Column(expression: 'SELECT 2')
+  int two;
+}
+
+@serializable
+@orm
+class _Alphabet extends Model {
+  String value;
+
+  @belongsTo
+  _Numbers numbers;
+}

angel_orm_test/lib/src/models/custom_expr.g.dart

@@ -0,0 +1,538 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'custom_expr.dart';
+
+// **************************************************************************
+// MigrationGenerator
+// **************************************************************************
+
+class NumbersMigration extends Migration {
+  @override
+  up(Schema schema) {
+    schema.create('numbers', (table) {
+      table.serial('id')..primaryKey();
+      table.timeStamp('created_at');
+      table.timeStamp('updated_at');
+    });
+  }
+
+  @override
+  down(Schema schema) {
+    schema.drop('numbers');
+  }
+}
+
+class AlphabetMigration extends Migration {
+  @override
+  up(Schema schema) {
+    schema.create('alphabets', (table) {
+      table.serial('id')..primaryKey();
+      table.timeStamp('created_at');
+      table.timeStamp('updated_at');
+      table.varChar('value');
+      table
+          .declare('numbers_id', ColumnType('serial'))
+          .references('numbers', 'id');
+    });
+  }
+
+  @override
+  down(Schema schema) {
+    schema.drop('alphabets');
+  }
+}
+
+// **************************************************************************
+// OrmGenerator
+// **************************************************************************
+
+class NumbersQuery extends Query<Numbers, NumbersQueryWhere> {
+  NumbersQuery({Query parent, Set<String> trampoline}) : super(parent: parent) {
+    trampoline ??= Set();
+    trampoline.add(tableName);
+    expressions['two'] = 'SELECT 2';
+    _where = NumbersQueryWhere(this);
+  }
+
+  @override
+  final NumbersQueryValues values = NumbersQueryValues();
+
+  NumbersQueryWhere _where;
+
+  @override
+  get casts {
+    return {};
+  }
+
+  @override
+  get tableName {
+    return 'numbers';
+  }
+
+  @override
+  get fields {
+    return const ['id', 'created_at', 'updated_at', 'two'];
+  }
+
+  @override
+  NumbersQueryWhere get where {
+    return _where;
+  }
+
+  @override
+  NumbersQueryWhere newWhereClause() {
+    return NumbersQueryWhere(this);
+  }
+
+  static Numbers parseRow(List row) {
+    if (row.every((x) => x == null)) return null;
+    var model = Numbers(
+        id: row[0].toString(),
+        createdAt: (row[1] as DateTime),
+        updatedAt: (row[2] as DateTime),
+        two: (row[3] as int));
+    return model;
+  }
+
+  @override
+  deserialize(List row) {
+    return parseRow(row);
+  }
+}
+
+class NumbersQueryWhere extends QueryWhere {
+  NumbersQueryWhere(NumbersQuery query)
+      : id = NumericSqlExpressionBuilder<int>(query, 'id'),
+        createdAt = DateTimeSqlExpressionBuilder(query, 'created_at'),
+        updatedAt = DateTimeSqlExpressionBuilder(query, 'updated_at');
+
+  final NumericSqlExpressionBuilder<int> id;
+
+  final DateTimeSqlExpressionBuilder createdAt;
+
+  final DateTimeSqlExpressionBuilder updatedAt;
+
+  @override
+  get expressionBuilders {
+    return [id, createdAt, updatedAt];
+  }
+}
+
+class NumbersQueryValues extends MapQueryValues {
+  @override
+  get casts {
+    return {};
+  }
+
+  String get id {
+    return (values['id'] as String);
+  }
+
+  set id(String value) => values['id'] = value;
+  DateTime get createdAt {
+    return (values['created_at'] as DateTime);
+  }
+
+  set createdAt(DateTime value) => values['created_at'] = value;
+  DateTime get updatedAt {
+    return (values['updated_at'] as DateTime);
+  }
+
+  set updatedAt(DateTime value) => values['updated_at'] = value;
+  void copyFrom(Numbers model) {
+    createdAt = model.createdAt;
+    updatedAt = model.updatedAt;
+  }
+}
+
+class AlphabetQuery extends Query<Alphabet, AlphabetQueryWhere> {
+  AlphabetQuery({Query parent, Set<String> trampoline})
+      : super(parent: parent) {
+    trampoline ??= Set();
+    trampoline.add(tableName);
+    _where = AlphabetQueryWhere(this);
+    leftJoin(_numbers = NumbersQuery(trampoline: trampoline, parent: this),
+        'numbers_id', 'id',
+        additionalFields: const ['id', 'created_at', 'updated_at', 'two'],
+        trampoline: trampoline);
+  }
+
+  @override
+  final AlphabetQueryValues values = AlphabetQueryValues();
+
+  AlphabetQueryWhere _where;
+
+  NumbersQuery _numbers;
+
+  @override
+  get casts {
+    return {};
+  }
+
+  @override
+  get tableName {
+    return 'alphabets';
+  }
+
+  @override
+  get fields {
+    return const ['id', 'created_at', 'updated_at', 'value', 'numbers_id'];
+  }
+
+  @override
+  AlphabetQueryWhere get where {
+    return _where;
+  }
+
+  @override
+  AlphabetQueryWhere newWhereClause() {
+    return AlphabetQueryWhere(this);
+  }
+
+  static Alphabet parseRow(List row) {
+    if (row.every((x) => x == null)) return null;
+    var model = Alphabet(
+        id: row[0].toString(),
+        createdAt: (row[1] as DateTime),
+        updatedAt: (row[2] as DateTime),
+        value: (row[3] as String));
+    if (row.length > 5) {
+      model = model.copyWith(
+          numbers: NumbersQuery.parseRow(row.skip(5).take(4).toList()));
+    }
+    return model;
+  }
+
+  @override
+  deserialize(List row) {
+    return parseRow(row);
+  }
+
+  NumbersQuery get numbers {
+    return _numbers;
+  }
+}
+
+class AlphabetQueryWhere extends QueryWhere {
+  AlphabetQueryWhere(AlphabetQuery query)
+      : id = NumericSqlExpressionBuilder<int>(query, 'id'),
+        createdAt = DateTimeSqlExpressionBuilder(query, 'created_at'),
+        updatedAt = DateTimeSqlExpressionBuilder(query, 'updated_at'),
+        value = StringSqlExpressionBuilder(query, 'value'),
+        numbersId = NumericSqlExpressionBuilder<int>(query, 'numbers_id');
+
+  final NumericSqlExpressionBuilder<int> id;
+
+  final DateTimeSqlExpressionBuilder createdAt;
+
+  final DateTimeSqlExpressionBuilder updatedAt;
+
+  final StringSqlExpressionBuilder value;
+
+  final NumericSqlExpressionBuilder<int> numbersId;
+
+  @override
+  get expressionBuilders {
+    return [id, createdAt, updatedAt, value, numbersId];
+  }
+}
+
+class AlphabetQueryValues extends MapQueryValues {
+  @override
+  get casts {
+    return {};
+  }
+
+  String get id {
+    return (values['id'] as String);
+  }
+
+  set id(String value) => values['id'] = value;
+  DateTime get createdAt {
+    return (values['created_at'] as DateTime);
+  }
+
+  set createdAt(DateTime value) => values['created_at'] = value;
+  DateTime get updatedAt {
+    return (values['updated_at'] as DateTime);
+  }
+
+  set updatedAt(DateTime value) => values['updated_at'] = value;
+  String get value {
+    return (values['value'] as String);
+  }
+
+  set value(String value) => values['value'] = value;
+  int get numbersId {
+    return (values['numbers_id'] as int);
+  }
+
+  set numbersId(int value) => values['numbers_id'] = value;
+  void copyFrom(Alphabet model) {
+    createdAt = model.createdAt;
+    updatedAt = model.updatedAt;
+    value = model.value;
+    if (model.numbers != null) {
+      values['numbers_id'] = model.numbers.id;
+    }
+  }
+}
+
+// **************************************************************************
+// JsonModelGenerator
+// **************************************************************************
+
+@generatedSerializable
+class Numbers extends _Numbers {
+  Numbers({this.id, this.createdAt, this.updatedAt, this.two});
+
+  /// A unique identifier corresponding to this item.
+  @override
+  String id;
+
+  /// The time at which this item was created.
+  @override
+  DateTime createdAt;
+
+  /// The last time at which this item was updated.
+  @override
+  DateTime updatedAt;
+
+  @override
+  int two;
+
+  Numbers copyWith(
+      {String id, DateTime createdAt, DateTime updatedAt, int two}) {
+    return Numbers(
+        id: id ?? this.id,
+        createdAt: createdAt ?? this.createdAt,
+        updatedAt: updatedAt ?? this.updatedAt,
+        two: two ?? this.two);
+  }
+
+  bool operator ==(other) {
+    return other is _Numbers &&
+        other.id == id &&
+        other.createdAt == createdAt &&
+        other.updatedAt == updatedAt &&
+        other.two == two;
+  }
+
+  @override
+  int get hashCode {
+    return hashObjects([id, createdAt, updatedAt, two]);
+  }
+
+  @override
+  String toString() {
+    return "Numbers(id=$id, createdAt=$createdAt, updatedAt=$updatedAt, two=$two)";
+  }
+
+  Map<String, dynamic> toJson() {
+    return NumbersSerializer.toMap(this);
+  }
+}
+
+@generatedSerializable
+class Alphabet extends _Alphabet {
+  Alphabet({this.id, this.createdAt, this.updatedAt, this.value, this.numbers});
+
+  /// A unique identifier corresponding to this item.
+  @override
+  String id;
+
+  /// The time at which this item was created.
+  @override
+  DateTime createdAt;
+
+  /// The last time at which this item was updated.
+  @override
+  DateTime updatedAt;
+
+  @override
+  String value;
+
+  @override
+  _Numbers numbers;
+
+  Alphabet copyWith(
+      {String id,
+      DateTime createdAt,
+      DateTime updatedAt,
+      String value,
+      _Numbers numbers}) {
+    return Alphabet(
+        id: id ?? this.id,
+        createdAt: createdAt ?? this.createdAt,
+        updatedAt: updatedAt ?? this.updatedAt,
+        value: value ?? this.value,
+        numbers: numbers ?? this.numbers);
+  }
+
+  bool operator ==(other) {
+    return other is _Alphabet &&
+        other.id == id &&
+        other.createdAt == createdAt &&
+        other.updatedAt == updatedAt &&
+        other.value == value &&
+        other.numbers == numbers;
+  }
+
+  @override
+  int get hashCode {
+    return hashObjects([id, createdAt, updatedAt, value, numbers]);
+  }
+
+  @override
+  String toString() {
+    return "Alphabet(id=$id, createdAt=$createdAt, updatedAt=$updatedAt, value=$value, numbers=$numbers)";
+  }
+
+  Map<String, dynamic> toJson() {
+    return AlphabetSerializer.toMap(this);
+  }
+}
+
+// **************************************************************************
+// SerializerGenerator
+// **************************************************************************
+
+const NumbersSerializer numbersSerializer = NumbersSerializer();
+
+class NumbersEncoder extends Converter<Numbers, Map> {
+  const NumbersEncoder();
+
+  @override
+  Map convert(Numbers model) => NumbersSerializer.toMap(model);
+}
+
+class NumbersDecoder extends Converter<Map, Numbers> {
+  const NumbersDecoder();
+
+  @override
+  Numbers convert(Map map) => NumbersSerializer.fromMap(map);
+}
+
+class NumbersSerializer extends Codec<Numbers, Map> {
+  const NumbersSerializer();
+
+  @override
+  get encoder => const NumbersEncoder();
+  @override
+  get decoder => const NumbersDecoder();
+  static Numbers fromMap(Map map) {
+    return Numbers(
+        id: map['id'] as String,
+        createdAt: map['created_at'] != null
+            ? (map['created_at'] is DateTime
+                ? (map['created_at'] as DateTime)
+                : DateTime.parse(map['created_at'].toString()))
+            : null,
+        updatedAt: map['updated_at'] != null
+            ? (map['updated_at'] is DateTime
+                ? (map['updated_at'] as DateTime)
+                : DateTime.parse(map['updated_at'].toString()))
+            : null,
+        two: map['two'] as int);
+  }
+
+  static Map<String, dynamic> toMap(_Numbers model) {
+    if (model == null) {
+      return null;
+    }
+    return {
+      'id': model.id,
+      'created_at': model.createdAt?.toIso8601String(),
+      'updated_at': model.updatedAt?.toIso8601String(),
+      'two': model.two
+    };
+  }
+}
+
+abstract class NumbersFields {
+  static const List<String> allFields = <String>[id, createdAt, updatedAt, two];
+
+  static const String id = 'id';
+
+  static const String createdAt = 'created_at';
+
+  static const String updatedAt = 'updated_at';
+
+  static const String two = 'two';
+}
+
+const AlphabetSerializer alphabetSerializer = AlphabetSerializer();
+
+class AlphabetEncoder extends Converter<Alphabet, Map> {
+  const AlphabetEncoder();
+
+  @override
+  Map convert(Alphabet model) => AlphabetSerializer.toMap(model);
+}
+
+class AlphabetDecoder extends Converter<Map, Alphabet> {
+  const AlphabetDecoder();
+
+  @override
+  Alphabet convert(Map map) => AlphabetSerializer.fromMap(map);
+}
+
+class AlphabetSerializer extends Codec<Alphabet, Map> {
+  const AlphabetSerializer();
+
+  @override
+  get encoder => const AlphabetEncoder();
+  @override
+  get decoder => const AlphabetDecoder();
+  static Alphabet fromMap(Map map) {
+    return Alphabet(
+        id: map['id'] as String,
+        createdAt: map['created_at'] != null
+            ? (map['created_at'] is DateTime
+                ? (map['created_at'] as DateTime)
+                : DateTime.parse(map['created_at'].toString()))
+            : null,
+        updatedAt: map['updated_at'] != null
+            ? (map['updated_at'] is DateTime
+                ? (map['updated_at'] as DateTime)
+                : DateTime.parse(map['updated_at'].toString()))
+            : null,
+        value: map['value'] as String,
+        numbers: map['numbers'] != null
+            ? NumbersSerializer.fromMap(map['numbers'] as Map)
+            : null);
+  }
+
+  static Map<String, dynamic> toMap(_Alphabet model) {
+    if (model == null) {
+      return null;
+    }
+    return {
+      'id': model.id,
+      'created_at': model.createdAt?.toIso8601String(),
+      'updated_at': model.updatedAt?.toIso8601String(),
+      'value': model.value,
+      'numbers': NumbersSerializer.toMap(model.numbers)
+    };
+  }
+}
+
+abstract class AlphabetFields {
+  static const List<String> allFields = <String>[
+    id,
+    createdAt,
+    updatedAt,
+    value,
+    numbers
+  ];
+
+  static const String id = 'id';
+
+  static const String createdAt = 'created_at';
+
+  static const String updatedAt = 'updated_at';
+
+  static const String value = 'value';
+
+  static const String numbers = 'numbers';
+}