anchor.diff:  
   part 'todos.g.dart';
   
  +mixin AutoIncrement on Table {
  +  IntColumn get id => integer().autoIncrement()();
  +}
  +
   @DataClassName('TodoEntry')
  -class TodosTable extends Table {
  +class TodosTable extends Table with AutoIncrement {
     @override
     String get tableName => 'todos';
   
  -  IntColumn get id => integer().autoIncrement()();
     TextColumn get title => text().withLength(min: 4, max: 16).nullable()();
     TextColumn get content => text()();
     @JsonKey('target_date')
  
positive.code: }
  
  @DataClassName('Category')
  class Categories extends Table {
    IntColumn get id => integer().autoIncrement()();
    TextColumn get description =>
        text().named('desc').customConstraint('NOT NULL UNIQUE')();
  }
  
negative.code:   TextColumn get custom => text().map(const CustomConverter())();
  }
  
  class PureDefaults extends Table with AutoIncrement {
    TextColumn get txt => text().nullable()();
  }
  
  