While using two tables, getting error importing moor

Question

    import 'dart:async';

    import 'package:moor_flutter/moor_flutter.dart';

    part 'tables.g.dart';

    //Adds a Categorys table...

    class Categorys extends Table {
      IntColumn get cid => integer().named('cid').autoIncrement()();
      TextColumn get ctitle => text().named('ctitle')();
      DateTimeColumn get ctimestamp => dateTime().named('ctimestamp')();
      TextColumn get mategorymtitle =>
          text().nullable().customConstraint('NULL REFERENCES mategorys(mtitle)')();
    }

     //Adds a Mategory table...

    class Mategorys extends Table {
      //IntColumn get mid => integer().named('mid').autoIncrement()();
      TextColumn get mtitle => text().named('mtitle')();
      DateTimeColumn get mtimestamp => dateTime().named('mtimestamp')();
      //IntColumn get cid => integer().named('cid')();

      @override
      Set<Column> get primaryKey => {mtitle};
    }

    //Adds a CategorywithMategory class...

    class CategoryWithMategory {
      final Category category;
      final Mategory mategory;

      CategoryWithMategory({
        @required this.category,
        @required this.mategory,
      });
    }

    //Adds a MyDatabase class...

    @UseMoor(tables: [Categorys, Mategorys], daos: [CategorysDao, MategorysDao])
    class MyDatabase extends _$MyDatabase {
      MyDatabase()
          : super(FlutterQueryExecutor.inDatabaseFolder(
              path: 'db.sqlite',
            ));

      @override
      int get schemaVersion => 1;
    }

    //Adds a CategorysDao name...    

    @UseDao(tables: [Categorys,Mategorys])
    class CategorysDao extends DatabaseAccessor<MyDatabase>
        with _$CategorysDaoMixin {
      CategorysDao(MyDatabase db) : super(db);

      Stream<List<CategoryWithMategory>> watchAllCategorys() {
        return (select(categorys)
              ..orderBy(
                [
                  (t) => OrderingTerm(expression: t.cid, mode: OrderingMode.asc),
                  (t) => OrderingTerm(expression: t.mategorymtitle),
                ],
              ))
            .join(
              [
                leftOuterJoin(mategorys,
                    mategorys.mtitle.equalsExp(categorys.mategorymtitle)),
              ],
            )
            .watch()
            .map((rows) => rows.map(
                  (row) {
                    return CategoryWithMategory(
                      category: row.readTable(categorys),
                      mategory: row.readTable(mategorys),
                    );
                  },
                ).toList());
      }



      Future<List<Category>> get allWatchingCategorys => select(categorys).get();

      //Adds a category name...
      void addCategory({String ctitle, DateTime ctimestamp}) {
        final _entry = CategorysCompanion(
          ctitle: Value(ctitle),
          ctimestamp: Value(ctimestamp),
        );
        into(categorys).insert(_entry);
      }

      //Updates a category name...
      void updateCategory({String ctitle, DateTime ctimestamp}) {
        final _entry = CategorysCompanion(
          ctitle: Value(ctitle),
          ctimestamp: Value(ctimestamp),
        );
        update(categorys).write(_entry);
      }
    }

    //Adds a MategoryDao name...
    class MategorysDao extends DatabaseAccessor<MyDatabase>
        with _$MategorysDaoMixin {
      MategorysDao(MyDatabase db) : super(db);

      Future<List<Mategory>> get allWatchingMategorys => select(mategorys).get();
      Stream<List<Mategory>> get watchAllMategorys => select(mategorys).watch();

      //Adds a mategory name...
      void addMategory({String mtitle, DateTime mtimestamp}) {
        final _entry = MategorysCompanion(
          mtitle: Value(mtitle),
          mtimestamp: Value(mtimestamp),
        );
        into(mategorys).insert(_entry);
      }

      //Updates a mategory name...
      void updateMategory({String mtitle, DateTime mtimestamp}) {
        final _entry = MategorysCompanion(
          mtitle: Value(mtitle),
          mtimestamp: Value(mtimestamp),
        );
        update(mategorys).write(_entry);
      }
    }

**I made this program in dart in android studio. It has two tables Categorys and Mategorys. Mategorys is nothing but sublist of Categorys. The above program in flutter is showing error in CatgorysDao class, in leftouterjoin inside watchAllCategorys method due to mategorys. Couldn't understand why. Can anybody find out the error please? I am not able to write correct program with two or more tables using moor library in flutter. Please help...

Answer 1

You forgot to add a table in your MategorysDao

//Adds a MategoryDao name...
    class MategorysDao extends DatabaseAccessor<MyDatabase>
        with _$MategorysDaoMixin {}

Change this with

@UseDao(tables:[Mategory])
 class MategorysDao extends DatabaseAccessor<MyDatabase>
            with _$MategorysDaoMixin {}