Simplify n:m example with json functions

docs/lib/snippets/modular/many_to_many/json.dart

@@ -0,0 +1,139 @@
+import 'package:drift/drift.dart';
+import 'package:drift/extensions/json1.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+import 'json.drift.dart';
+import 'shared.dart' show BuyableItems;
+import 'shared.drift.dart';
+
+part 'json.g.dart';
+
+typedef ShoppingCartWithItems = ({
+  ShoppingCart cart,
+  List<BuyableItem> items,
+});
+
+// #docregion tables
+@DataClassName('ShoppingCart')
+class ShoppingCarts extends Table {
+  IntColumn get id => integer().autoIncrement()();
+  TextColumn get entries => text().map(ShoppingCartEntries.converter)();
+
+  // we could also store some further information about the user creating
+  // this cart etc.
+}
+
+@JsonSerializable()
+class ShoppingCartEntries {
+  final List<int> items;
+
+  ShoppingCartEntries({required this.items});
+
+  factory ShoppingCartEntries.fromJson(Map<String, Object?> json) =>
+      _$ShoppingCartEntriesFromJson(json);
+
+  Map<String, Object?> toJson() {
+    return _$ShoppingCartEntriesToJson(this);
+  }
+
+  static JsonTypeConverter<ShoppingCartEntries, String> converter =
+      TypeConverter.json(
+    fromJson: (json) =>
+        ShoppingCartEntries.fromJson(json as Map<String, Object?>),
+    toJson: (entries) => entries.toJson(),
+  );
+}
+
+// #enddocregion tables
+
+@DriftDatabase(tables: [BuyableItems, ShoppingCarts])
+class JsonBasedDatabase extends $JsonBasedDatabase {
+  JsonBasedDatabase(QueryExecutor e) : super(e);
+
+  @override
+  int get schemaVersion => 1;
+
+  // #docregion createEmptyCart
+  Future<ShoppingCartWithItems> createEmptyCart() async {
+    final cart = await into(shoppingCarts)
+        .insertReturning(const ShoppingCartsCompanion());
+
+    // we set the items property to [] because we've just created the cart - it
+    // will be empty
+    return (cart: cart, items: <BuyableItem>[]);
+  }
+  // #enddocregion createEmptyCart
+
+  // #docregion updateCart
+  Future<void> updateCart(ShoppingCartWithItems entry) async {
+    await update(shoppingCarts).replace(entry.cart.copyWith(
+        entries: ShoppingCartEntries(items: [
+      for (final item in entry.items) item.id,
+    ])));
+  }
+  // #enddocregion updateCart
+
+  // #docregion watchCart
+  Stream<ShoppingCartWithItems> watchCart(int id) {
+    final referencedItems = shoppingCarts.entries.jsonEach(this, r'#$.items');
+
+    final cartWithEntries = select(shoppingCarts).join(
+      [
+        // Join every referenced item from the json array
+        innerJoin(referencedItems, const Constant(true), useColumns: false),
+        // And use that to join the items
+        innerJoin(
+          buyableItems,
+          buyableItems.id.equalsExp(referencedItems.value.cast()),
+        ),
+      ],
+    )..where(shoppingCarts.id.equals(id));
+
+    return cartWithEntries.watch().map((rows) {
+      late ShoppingCart cart;
+      final entries = <BuyableItem>[];
+
+      for (final row in rows) {
+        cart = row.readTable(shoppingCarts);
+        entries.add(row.readTable(buyableItems));
+      }
+
+      return (cart: cart, items: entries);
+    });
+  }
+  // #enddocregion watchCart
+
+  // #docregion watchAllCarts
+  Stream<List<ShoppingCartWithItems>> watchAllCarts() {
+    final referencedItems = shoppingCarts.entries.jsonEach(this, r'#$.items');
+
+    final cartWithEntries = select(shoppingCarts).join(
+      [
+        // Join every referenced item from the json array
+        innerJoin(referencedItems, const Constant(true), useColumns: false),
+        // And use that to join the items
+        innerJoin(
+          buyableItems,
+          buyableItems.id.equalsExp(referencedItems.value.cast()),
+        ),
+      ],
+    );
+
+    return cartWithEntries.watch().map((rows) {
+      final entriesByCart = <ShoppingCart, List<BuyableItem>>{};
+
+      for (final row in rows) {
+        final cart = row.readTable(shoppingCarts);
+        final item = row.readTable(buyableItems);
+
+        entriesByCart.putIfAbsent(cart, () => []).add(item);
+      }
+
+      return [
+        for (final entry in entriesByCart.entries)
+          (cart: entry.key, items: entry.value)
+      ];
+    });
+  }
+  // #enddocregion watchAllCarts
+}

docs/lib/snippets/modular/many_to_many/json.drift.dart

@@ -0,0 +1,203 @@
+// ignore_for_file: type=lint
+import 'package:drift/drift.dart' as i0;
+import 'package:drift_docs/snippets/modular/many_to_many/shared.drift.dart'
+    as i1;
+import 'package:drift_docs/snippets/modular/many_to_many/json.drift.dart' as i2;
+import 'package:drift_docs/snippets/modular/many_to_many/json.dart' as i3;
+
+abstract class $JsonBasedDatabase extends i0.GeneratedDatabase {
+  $JsonBasedDatabase(i0.QueryExecutor e) : super(e);
+  late final i1.$BuyableItemsTable buyableItems = i1.$BuyableItemsTable(this);
+  late final i2.$ShoppingCartsTable shoppingCarts =
+      i2.$ShoppingCartsTable(this);
+  @override
+  Iterable<i0.TableInfo<i0.Table, Object?>> get allTables =>
+      allSchemaEntities.whereType<i0.TableInfo<i0.Table, Object?>>();
+  @override
+  List<i0.DatabaseSchemaEntity> get allSchemaEntities =>
+      [buyableItems, shoppingCarts];
+}
+
+class $ShoppingCartsTable extends i3.ShoppingCarts
+    with i0.TableInfo<$ShoppingCartsTable, i2.ShoppingCart> {
+  @override
+  final i0.GeneratedDatabase attachedDatabase;
+  final String? _alias;
+  $ShoppingCartsTable(this.attachedDatabase, [this._alias]);
+  static const i0.VerificationMeta _idMeta = const i0.VerificationMeta('id');
+  @override
+  late final i0.GeneratedColumn<int> id = i0.GeneratedColumn<int>(
+      'id', aliasedName, false,
+      hasAutoIncrement: true,
+      type: i0.DriftSqlType.int,
+      requiredDuringInsert: false,
+      defaultConstraints:
+          i0.GeneratedColumn.constraintIsAlways('PRIMARY KEY AUTOINCREMENT'));
+  static const i0.VerificationMeta _entriesMeta =
+      const i0.VerificationMeta('entries');
+  @override
+  late final i0.GeneratedColumnWithTypeConverter<i3.ShoppingCartEntries, String>
+      entries = i0.GeneratedColumn<String>('entries', aliasedName, false,
+              type: i0.DriftSqlType.string, requiredDuringInsert: true)
+          .withConverter<i3.ShoppingCartEntries>(
+              i2.$ShoppingCartsTable.$converterentries);
+  @override
+  List<i0.GeneratedColumn> get $columns => [id, entries];
+  @override
+  String get aliasedName => _alias ?? actualTableName;
+  @override
+  String get actualTableName => $name;
+  static const String $name = 'shopping_carts';
+  @override
+  i0.VerificationContext validateIntegrity(
+      i0.Insertable<i2.ShoppingCart> instance,
+      {bool isInserting = false}) {
+    final context = i0.VerificationContext();
+    final data = instance.toColumns(true);
+    if (data.containsKey('id')) {
+      context.handle(_idMeta, id.isAcceptableOrUnknown(data['id']!, _idMeta));
+    }
+    context.handle(_entriesMeta, const i0.VerificationResult.success());
+    return context;
+  }
+
+  @override
+  Set<i0.GeneratedColumn> get $primaryKey => {id};
+  @override
+  i2.ShoppingCart map(Map<String, dynamic> data, {String? tablePrefix}) {
+    final effectivePrefix = tablePrefix != null ? '$tablePrefix.' : '';
+    return i2.ShoppingCart(
+      id: attachedDatabase.typeMapping
+          .read(i0.DriftSqlType.int, data['${effectivePrefix}id'])!,
+      entries: i2.$ShoppingCartsTable.$converterentries.fromSql(attachedDatabase
+          .typeMapping
+          .read(i0.DriftSqlType.string, data['${effectivePrefix}entries'])!),
+    );
+  }
+
+  @override
+  $ShoppingCartsTable createAlias(String alias) {
+    return $ShoppingCartsTable(attachedDatabase, alias);
+  }
+
+  static i0.JsonTypeConverter2<i3.ShoppingCartEntries, String, String>
+      $converterentries = i3.ShoppingCartEntries.converter;
+}
+
+class ShoppingCart extends i0.DataClass
+    implements i0.Insertable<i2.ShoppingCart> {
+  final int id;
+  final i3.ShoppingCartEntries entries;
+  const ShoppingCart({required this.id, required this.entries});
+  @override
+  Map<String, i0.Expression> toColumns(bool nullToAbsent) {
+    final map = <String, i0.Expression>{};
+    map['id'] = i0.Variable<int>(id);
+    {
+      final converter = i2.$ShoppingCartsTable.$converterentries;
+      map['entries'] = i0.Variable<String>(converter.toSql(entries));
+    }
+    return map;
+  }
+
+  i2.ShoppingCartsCompanion toCompanion(bool nullToAbsent) {
+    return i2.ShoppingCartsCompanion(
+      id: i0.Value(id),
+      entries: i0.Value(entries),
+    );
+  }
+
+  factory ShoppingCart.fromJson(Map<String, dynamic> json,
+      {i0.ValueSerializer? serializer}) {
+    serializer ??= i0.driftRuntimeOptions.defaultSerializer;
+    return ShoppingCart(
+      id: serializer.fromJson<int>(json['id']),
+      entries: i2.$ShoppingCartsTable.$converterentries
+          .fromJson(serializer.fromJson<String>(json['entries'])),
+    );
+  }
+  @override
+  Map<String, dynamic> toJson({i0.ValueSerializer? serializer}) {
+    serializer ??= i0.driftRuntimeOptions.defaultSerializer;
+    return <String, dynamic>{
+      'id': serializer.toJson<int>(id),
+      'entries': serializer.toJson<String>(
+          i2.$ShoppingCartsTable.$converterentries.toJson(entries)),
+    };
+  }
+
+  i2.ShoppingCart copyWith({int? id, i3.ShoppingCartEntries? entries}) =>
+      i2.ShoppingCart(
+        id: id ?? this.id,
+        entries: entries ?? this.entries,
+      );
+  @override
+  String toString() {
+    return (StringBuffer('ShoppingCart(')
+          ..write('id: $id, ')
+          ..write('entries: $entries')
+          ..write(')'))
+        .toString();
+  }
+
+  @override
+  int get hashCode => Object.hash(id, entries);
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      (other is i2.ShoppingCart &&
+          other.id == this.id &&
+          other.entries == this.entries);
+}
+
+class ShoppingCartsCompanion extends i0.UpdateCompanion<i2.ShoppingCart> {
+  final i0.Value<int> id;
+  final i0.Value<i3.ShoppingCartEntries> entries;
+  const ShoppingCartsCompanion({
+    this.id = const i0.Value.absent(),
+    this.entries = const i0.Value.absent(),
+  });
+  ShoppingCartsCompanion.insert({
+    this.id = const i0.Value.absent(),
+    required i3.ShoppingCartEntries entries,
+  }) : entries = i0.Value(entries);
+  static i0.Insertable<i2.ShoppingCart> custom({
+    i0.Expression<int>? id,
+    i0.Expression<String>? entries,
+  }) {
+    return i0.RawValuesInsertable({
+      if (id != null) 'id': id,
+      if (entries != null) 'entries': entries,
+    });
+  }
+
+  i2.ShoppingCartsCompanion copyWith(
+      {i0.Value<int>? id, i0.Value<i3.ShoppingCartEntries>? entries}) {
+    return i2.ShoppingCartsCompanion(
+      id: id ?? this.id,
+      entries: entries ?? this.entries,
+    );
+  }
+
+  @override
+  Map<String, i0.Expression> toColumns(bool nullToAbsent) {
+    final map = <String, i0.Expression>{};
+    if (id.present) {
+      map['id'] = i0.Variable<int>(id.value);
+    }
+    if (entries.present) {
+      final converter = i2.$ShoppingCartsTable.$converterentries;
+      map['entries'] = i0.Variable<String>(converter.toSql(entries.value));
+    }
+    return map;
+  }
+
+  @override
+  String toString() {
+    return (StringBuffer('ShoppingCartsCompanion(')
+          ..write('id: $id, ')
+          ..write('entries: $entries')
+          ..write(')'))
+        .toString();
+  }
+}