Extract custom Dart table constraints into schema

drift/lib/src/runtime/query_builder/migration.dart

@@ -272,38 +272,40 @@ class Migrator {
 
     final dslTable = table.asDslTable;
 
-    // we're in a bit of a hacky situation where we don't write the primary
-    // as table constraint if it has already been written on a primary key
-    // column, even though that column appears in table.$primaryKey because we
-    // need to know all primary keys for the update(table).replace(row) API
-    final hasPrimaryKey = table.$primaryKey.isNotEmpty;
-    final dontWritePk = dslTable.dontWriteConstraints || hasAutoIncrement;
-    if (hasPrimaryKey && !dontWritePk) {
-      context.buffer.write(', PRIMARY KEY (');
-      final pkList = table.$primaryKey.toList(growable: false);
-      for (var i = 0; i < pkList.length; i++) {
-        final column = pkList[i];
+    if (!dslTable.dontWriteConstraints) {
+      final hasPrimaryKey = table.$primaryKey.isNotEmpty;
 
-        context.buffer.write(column.escapedName);
-
-        if (i != pkList.length - 1) context.buffer.write(', ');
-      }
-      context.buffer.write(')');
-    }
-
-    if (table.uniqueKeys.isNotEmpty) {
-      for (final key in table.uniqueKeys) {
-        context.buffer.write(', UNIQUE (');
-        final uqList = key.toList(growable: false);
-        for (var i = 0; i < uqList.length; i++) {
-          final column = uqList[i];
+      // we're in a bit of a hacky situation where we don't write the primary
+      // as table constraint if it has already been written on a primary key
+      // column, even though that column appears in table.$primaryKey because we
+      // need to know all primary keys for the update(table).replace(row) API
+      if (hasPrimaryKey && !hasAutoIncrement) {
+        context.buffer.write(', PRIMARY KEY (');
+        final pkList = table.$primaryKey.toList(growable: false);
+        for (var i = 0; i < pkList.length; i++) {
+          final column = pkList[i];
 
           context.buffer.write(column.escapedName);
 
-          if (i != uqList.length - 1) context.buffer.write(', ');
+          if (i != pkList.length - 1) context.buffer.write(', ');
         }
         context.buffer.write(')');
       }
+
+      if (table.uniqueKeys.isNotEmpty) {
+        for (final key in table.uniqueKeys) {
+          context.buffer.write(', UNIQUE (');
+          final uqList = key.toList(growable: false);
+          for (var i = 0; i < uqList.length; i++) {
+            final column = uqList[i];
+
+            context.buffer.write(column.escapedName);
+
+            if (i != uqList.length - 1) context.buffer.write(', ');
+          }
+          context.buffer.write(')');
+        }
+      }
     }
 
     final constraints = dslTable.customConstraints;

drift/test/generated/custom_tables.g.dart

@@ -1029,6 +1029,10 @@ class Mytable extends Table with TableInfo<Mytable, MytableData> {
   @override
   Set<GeneratedColumn> get $primaryKey => {someid};
   @override
+  List<Set<GeneratedColumn>> get uniqueKeys => [
+        {sometext, isInserting},
+      ];
+  @override
   MytableData map(Map<String, dynamic> data, {String? tablePrefix}) {
     final effectivePrefix = tablePrefix != null ? '$tablePrefix.' : '';
     return MytableData(
@@ -1049,7 +1053,8 @@ class Mytable extends Table with TableInfo<Mytable, MytableData> {
   }
 
   @override
-  List<String> get customConstraints => const ['PRIMARY KEY(someid DESC)'];
+  List<String> get customConstraints =>
+      const ['PRIMARY KEY(someid DESC)', 'UNIQUE(sometext, is_inserting)'];
   @override
   bool get dontWriteConstraints => true;
 }

drift/test/generated/tables.drift

@@ -32,7 +32,8 @@ CREATE TABLE mytable (
     sometext TEXT,
     is_inserting BOOLEAN,
     somedate DATETIME,
-    PRIMARY KEY (someid DESC)
+    PRIMARY KEY (someid DESC),
+    UNIQUE (sometext, is_inserting)
 );
 
 CREATE VIRTUAL TABLE email USING fts5(sender, title, body) AS EMail;

drift/test/integration_tests/drift_files_test.dart

@@ -29,7 +29,8 @@ const _createMyTable = 'CREATE TABLE IF NOT EXISTS "mytable" ('
     '"sometext" TEXT, '
     '"is_inserting" INTEGER, '
     '"somedate" TEXT, '
-    'PRIMARY KEY(someid DESC)'
+    'PRIMARY KEY(someid DESC), '
+    'UNIQUE(sometext, is_inserting)'
     ');';
 
 const _createEmail = 'CREATE VIRTUAL TABLE IF NOT EXISTS "email" USING '

drift_dev/lib/src/analysis/resolver/dart/table.dart

@@ -61,6 +61,7 @@ class DartTableResolver extends LocalElementResolver<DiscoveredDartTable> {
         for (final uniqueKey in uniqueKeys ?? const <Set<DriftColumn>>[])
           UniqueColumns(uniqueKey),
       ],
+      overrideTableConstraints: await _readCustomConstraints(element),
       withoutRowId: await _overrideWithoutRowId(element) ?? false,
     );
 
@@ -330,4 +331,44 @@ class DartTableResolver extends LocalElementResolver<DiscoveredDartTable> {
       MethodDeclaration declaration, Element element) async {
     return ColumnParser(this).parse(declaration, element);
   }
+
+  Future<List<String>> _readCustomConstraints(ClassElement element) async {
+    final customConstraints =
+        element.lookUpGetter('customConstraints', element.library);
+
+    if (customConstraints == null || customConstraints.isFromDefaultTable) {
+      // Does not define custom constraints
+      return const [];
+    }
+
+    final ast = await resolver.driver.backend
+        .loadElementDeclaration(customConstraints) as MethodDeclaration;
+    final body = ast.body;
+    if (body is! ExpressionFunctionBody) {
+      reportError(DriftAnalysisError.forDartElement(customConstraints,
+          'This must return a list literal with the => syntax'));
+      return const [];
+    }
+    final expression = body.expression;
+    final foundConstraints = <String>[];
+
+    if (expression is ListLiteral) {
+      for (final entry in expression.elements) {
+        if (entry is StringLiteral) {
+          final value = entry.stringValue;
+          if (value != null) {
+            foundConstraints.add(value);
+          }
+        } else {
+          reportError(DriftAnalysisError.inDartAst(
+              element, entry, 'This must be a string literal.'));
+        }
+      }
+    } else {
+      reportError(DriftAnalysisError.forDartElement(
+          customConstraints, 'This must return a list literal!'));
+    }
+
+    return foundConstraints;
+  }
 }

drift_dev/lib/src/writer/tables/table_writer.dart

@@ -507,7 +507,12 @@ class TableWriter extends TableOrViewWriter {
         ..write('bool get isStrict => true;\n');
     }
 
-    if (table.overrideTableConstraints != null) {
+    // For Dart tables, the user already overrides the `customConstraints`
+    // getter in the source. So, since we extend that class by default, there's
+    // no need to override them again.
+    final writeTableConstraints = table.definingDartClass == null ||
+        scope.generationOptions.forSchema != null;
+    if (writeTableConstraints && table.overrideTableConstraints != null) {
       final value =
           table.overrideTableConstraints!.map(asDartLiteral).join(', ');
 

drift_dev/test/analysis/resolver/dart/table_test.dart

@@ -288,4 +288,43 @@ class InvalidConstraints extends Table {
       ),
     );
   });
+
+  test('reads custom constraints from table', () async {
+    final backend = TestBackend.inTest({
+      'a|lib/a.dart': '''
+import 'package:drift/drift.dart';
+
+class BadTable extends Table {
+  IntColumn get id => integer().autoIncrement()();
+
+  @override
+  List<String> get customConstraints => constructConstraints();
+}
+
+class WithConstraints extends Table {
+  IntColumn get id => integer().autoIncrement()();
+
+  @override
+  List<String> get customConstraints => [
+    1, 'two', 'three'
+  ];
+}
+'''
+    });
+
+    final state = await backend.analyze('package:a/a.dart');
+    final badTable = state.analysis[state.id('bad_table')]!;
+    final withConstraints = state.analysis[state.id('with_constraints')]!;
+
+    expect((badTable.result as DriftTable).overrideTableConstraints, []);
+    //expect(withConstraints.overrideTableConstraints, ['two', 'three']);
+
+    expect(state.errorsDuringDiscovery, isEmpty);
+    expect(badTable.errorsDuringAnalysis, [
+      isDriftError('This must return a list literal!')
+          .withSpan('customConstraints')
+    ]);
+    expect(withConstraints.errorsDuringAnalysis,
+        [isDriftError('This must be a string literal.').withSpan('1')]);
+  });
 }

examples/migrations_example/drift_migrations/drift_schema_v9.json

@@ -0,0 +1 @@
+{"_meta":{"description":"This file contains a serialized version of schema entities for drift.","version":"1.0.0"},"options":{"store_date_time_values_as_text":true},"entities":[{"id":0,"references":[],"type":"table","data":{"name":"users","was_declared_in_moor":false,"columns":[{"name":"id","getter_name":"id","moor_type":"ColumnType.integer","nullable":false,"customConstraints":null,"defaultConstraints":"PRIMARY KEY AUTOINCREMENT","default_dart":null,"default_client_dart":null,"dsl_features":["auto-increment"]},{"name":"name","getter_name":"name","moor_type":"ColumnType.text","nullable":false,"customConstraints":null,"default_dart":"const Constant('name')","default_client_dart":null,"dsl_features":[]},{"name":"birthday","getter_name":"birthday","moor_type":"ColumnType.datetime","nullable":true,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"next_user","getter_name":"nextUser","moor_type":"ColumnType.integer","nullable":true,"customConstraints":null,"defaultConstraints":"REFERENCES users (id)","default_dart":null,"default_client_dart":null,"dsl_features":["unknown"]}],"is_virtual":false,"without_rowid":false,"constraints":["CHECK (LENGTH(name) < 10)"],"unique_keys":[["name","birthday"]]}},{"id":1,"references":[0],"type":"table","data":{"name":"groups","was_declared_in_moor":true,"columns":[{"name":"id","getter_name":"id","moor_type":"ColumnType.integer","nullable":false,"customConstraints":"NOT NULL","default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"title","getter_name":"title","moor_type":"ColumnType.text","nullable":false,"customConstraints":"NOT NULL","default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"deleted","getter_name":"deleted","moor_type":"ColumnType.boolean","nullable":true,"customConstraints":"DEFAULT FALSE","default_dart":"const CustomExpression('FALSE')","default_client_dart":null,"dsl_features":[]},{"name":"owner","getter_name":"owner","moor_type":"ColumnType.integer","nullable":false,"customConstraints":"NOT NULL REFERENCES users(id)","default_dart":null,"default_client_dart":null,"dsl_features":["unknown"]}],"is_virtual":false,"without_rowid":false,"constraints":["PRIMARY KEY(id)"],"explicit_pk":["id"]}},{"id":2,"references":[],"type":"table","data":{"name":"notes","was_declared_in_moor":true,"columns":[{"name":"title","getter_name":"title","moor_type":"ColumnType.text","nullable":false,"customConstraints":"","default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"content","getter_name":"content","moor_type":"ColumnType.text","nullable":false,"customConstraints":"","default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"search_terms","getter_name":"searchTerms","moor_type":"ColumnType.text","nullable":false,"customConstraints":"","default_dart":null,"default_client_dart":null,"dsl_features":[]}],"is_virtual":true,"create_virtual_stmt":"CREATE VIRTUAL TABLE \"notes\" USING fts5(title, content, search_terms, tokenize = \"unicode61 tokenchars '.'\")","without_rowid":false,"constraints":[]}},{"id":3,"references":[1,0],"type":"view","data":{"name":"group_count","sql":"CREATE VIEW group_count AS SELECT\n    users.*,\n    (SELECT COUNT(*) FROM \"groups\" WHERE owner = users.id) AS group_count\n  FROM users;","dart_data_name":"GroupCountData","dart_info_name":"GroupCount","columns":[{"name":"id","getter_name":"id","moor_type":"ColumnType.integer","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"name","getter_name":"name","moor_type":"ColumnType.text","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"birthday","getter_name":"birthday","moor_type":"ColumnType.datetime","nullable":true,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"next_user","getter_name":"nextUser","moor_type":"ColumnType.integer","nullable":true,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]},{"name":"group_count","getter_name":"groupCount","moor_type":"ColumnType.integer","nullable":false,"customConstraints":null,"default_dart":null,"default_client_dart":null,"dsl_features":[]}]}}]}

examples/migrations_example/lib/database.dart

@@ -3,13 +3,16 @@ import 'package:drift/drift.dart';
 import 'tables.dart';
 import 'src/generated/schema_v2.dart' as v2;
 import 'src/generated/schema_v4.dart' as v4;
+import 'src/generated/schema_v8.dart' as v8;
 
 part 'database.g.dart';
 
 @DriftDatabase(include: {'tables.drift'})
 class Database extends _$Database {
+  static const latestSchemaVersion = 9;
+
   @override
-  int get schemaVersion => 8;
+  int get schemaVersion => latestSchemaVersion;
 
   Database(DatabaseConnection connection) : super.connect(connection);
 
@@ -60,7 +63,18 @@ class Database extends _$Database {
               break;
             case 8:
               // Added a unique key to the users table
+
+              // TODO: Figure out why dropping the view is necessary (https://sqlite.org/forum/forumpost/de614349cb)
+              await m.drop(groupCount);
+              await m.alterTable(TableMigration(v8.Users(this)));
+              await m.recreateAllViews();
+              break;
+            case 9:
+              // Added a check to the users table
+              await m.drop(groupCount);
               await m.alterTable(TableMigration(users));
+              await m.recreateAllViews();
+
               break;
           }
         }

examples/migrations_example/lib/src/generated/schema.dart

@@ -2,6 +2,7 @@
 //@dart=2.12
 import 'package:drift/drift.dart';
 import 'package:drift/internal/migrations.dart';
+import 'schema_v9.dart' as v9;
 import 'schema_v8.dart' as v8;
 import 'schema_v1.dart' as v1;
 import 'schema_v2.dart' as v2;
@@ -15,6 +16,8 @@ class GeneratedHelper implements SchemaInstantiationHelper {
   @override
   GeneratedDatabase databaseForVersion(QueryExecutor db, int version) {
     switch (version) {
+      case 9:
+        return v9.DatabaseAtV9(db);
       case 8:
         return v8.DatabaseAtV8(db);
       case 1:
@@ -32,7 +35,8 @@ class GeneratedHelper implements SchemaInstantiationHelper {
       case 3:
         return v3.DatabaseAtV3(db);
       default:
-        throw MissingSchemaException(version, const {8, 1, 2, 6, 7, 4, 5, 3});
+        throw MissingSchemaException(
+            version, const {9, 8, 1, 2, 6, 7, 4, 5, 3});
     }
   }
 }

examples/migrations_example/lib/src/generated/schema_v9.dart

@@ -0,0 +1,215 @@
+// GENERATED CODE, DO NOT EDIT BY HAND.
+//@dart=2.12
+import 'package:drift/drift.dart';
+
+class Users extends Table with TableInfo {
+  @override
+  final GeneratedDatabase attachedDatabase;
+  final String? _alias;
+  Users(this.attachedDatabase, [this._alias]);
+  late final GeneratedColumn<int> id = GeneratedColumn<int>(
+      'id', aliasedName, false,
+      hasAutoIncrement: true,
+      type: DriftSqlType.int,
+      requiredDuringInsert: false,
+      defaultConstraints:
+          GeneratedColumn.constraintIsAlways('PRIMARY KEY AUTOINCREMENT'));
+  late final GeneratedColumn<String> name = GeneratedColumn<String>(
+      'name', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: false,
+      defaultValue: const Constant('name'));
+  late final GeneratedColumn<DateTime> birthday = GeneratedColumn<DateTime>(
+      'birthday', aliasedName, true,
+      type: DriftSqlType.dateTime, requiredDuringInsert: false);
+  late final GeneratedColumn<int> nextUser = GeneratedColumn<int>(
+      'next_user', aliasedName, true,
+      type: DriftSqlType.int,
+      requiredDuringInsert: false,
+      defaultConstraints:
+          GeneratedColumn.constraintIsAlways('REFERENCES users (id)'));
+  @override
+  List<GeneratedColumn> get $columns => [id, name, birthday, nextUser];
+  @override
+  String get aliasedName => _alias ?? 'users';
+  @override
+  String get actualTableName => 'users';
+  @override
+  Set<GeneratedColumn> get $primaryKey => {id};
+  @override
+  List<Set<GeneratedColumn>> get uniqueKeys => [
+        {name, birthday},
+      ];
+  @override
+  Never map(Map<String, dynamic> data, {String? tablePrefix}) {
+    throw UnsupportedError('TableInfo.map in schema verification code');
+  }
+
+  @override
+  Users createAlias(String alias) {
+    return Users(attachedDatabase, alias);
+  }
+
+  @override
+  List<String> get customConstraints => const ['CHECK (LENGTH(name) < 10)'];
+}
+
+class Groups extends Table with TableInfo {
+  @override
+  final GeneratedDatabase attachedDatabase;
+  final String? _alias;
+  Groups(this.attachedDatabase, [this._alias]);
+  late final GeneratedColumn<int> id = GeneratedColumn<int>(
+      'id', aliasedName, false,
+      type: DriftSqlType.int,
+      requiredDuringInsert: false,
+      $customConstraints: 'NOT NULL');
+  late final GeneratedColumn<String> title = GeneratedColumn<String>(
+      'title', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: 'NOT NULL');
+  late final GeneratedColumn<bool> deleted = GeneratedColumn<bool>(
+      'deleted', aliasedName, true,
+      type: DriftSqlType.bool,
+      requiredDuringInsert: false,
+      $customConstraints: 'DEFAULT FALSE',
+      defaultValue: const CustomExpression('FALSE'));
+  late final GeneratedColumn<int> owner = GeneratedColumn<int>(
+      'owner', aliasedName, false,
+      type: DriftSqlType.int,
+      requiredDuringInsert: true,
+      $customConstraints: 'NOT NULL REFERENCES users(id)');
+  @override
+  List<GeneratedColumn> get $columns => [id, title, deleted, owner];
+  @override
+  String get aliasedName => _alias ?? 'groups';
+  @override
+  String get actualTableName => 'groups';
+  @override
+  Set<GeneratedColumn> get $primaryKey => {id};
+  @override
+  Never map(Map<String, dynamic> data, {String? tablePrefix}) {
+    throw UnsupportedError('TableInfo.map in schema verification code');
+  }
+
+  @override
+  Groups createAlias(String alias) {
+    return Groups(attachedDatabase, alias);
+  }
+
+  @override
+  List<String> get customConstraints => const ['PRIMARY KEY(id)'];
+  @override
+  bool get dontWriteConstraints => true;
+}
+
+class Notes extends Table with TableInfo, VirtualTableInfo {
+  @override
+  final GeneratedDatabase attachedDatabase;
+  final String? _alias;
+  Notes(this.attachedDatabase, [this._alias]);
+  late final GeneratedColumn<String> title = GeneratedColumn<String>(
+      'title', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: '');
+  late final GeneratedColumn<String> content = GeneratedColumn<String>(
+      'content', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: '');
+  late final GeneratedColumn<String> searchTerms = GeneratedColumn<String>(
+      'search_terms', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: '');
+  @override
+  List<GeneratedColumn> get $columns => [title, content, searchTerms];
+  @override
+  String get aliasedName => _alias ?? 'notes';
+  @override
+  String get actualTableName => 'notes';
+  @override
+  Set<GeneratedColumn> get $primaryKey => const {};
+  @override
+  Never map(Map<String, dynamic> data, {String? tablePrefix}) {
+    throw UnsupportedError('TableInfo.map in schema verification code');
+  }
+
+  @override
+  Notes createAlias(String alias) {
+    return Notes(attachedDatabase, alias);
+  }
+
+  @override
+  String get moduleAndArgs =>
+      'fts5(title, content, search_terms, tokenize = "unicode61 tokenchars \'.\'")';
+}
+
+class GroupCount extends ViewInfo<GroupCount, Never> implements HasResultSet {
+  final String? _alias;
+  @override
+  final DatabaseAtV9 attachedDatabase;
+  GroupCount(this.attachedDatabase, [this._alias]);
+  @override
+  List<GeneratedColumn> get $columns =>
+      [id, name, birthday, nextUser, groupCount];
+  @override
+  String get aliasedName => _alias ?? entityName;
+  @override
+  String get entityName => 'group_count';
+  @override
+  String get createViewStmt =>
+      'CREATE VIEW group_count AS SELECT\n    users.*,\n    (SELECT COUNT(*) FROM "groups" WHERE owner = users.id) AS group_count\n  FROM users;';
+  @override
+  GroupCount get asDslTable => this;
+  @override
+  Never map(Map<String, dynamic> data, {String? tablePrefix}) {
+    throw UnsupportedError('TableInfo.map in schema verification code');
+  }
+
+  late final GeneratedColumn<int> id =
+      GeneratedColumn<int>('id', aliasedName, false, type: DriftSqlType.int);
+  late final GeneratedColumn<String> name = GeneratedColumn<String>(
+      'name', aliasedName, false,
+      type: DriftSqlType.string);
+  late final GeneratedColumn<DateTime> birthday = GeneratedColumn<DateTime>(
+      'birthday', aliasedName, true,
+      type: DriftSqlType.dateTime);
+  late final GeneratedColumn<int> nextUser = GeneratedColumn<int>(
+      'next_user', aliasedName, true,
+      type: DriftSqlType.int);
+  late final GeneratedColumn<int> groupCount = GeneratedColumn<int>(
+      'group_count', aliasedName, false,
+      type: DriftSqlType.int);
+  @override
+  GroupCount createAlias(String alias) {
+    return GroupCount(attachedDatabase, alias);
+  }
+
+  @override
+  Query? get query => null;
+  @override
+  Set<String> get readTables => const {};
+}
+
+class DatabaseAtV9 extends GeneratedDatabase {
+  DatabaseAtV9(QueryExecutor e) : super(e);
+  DatabaseAtV9.connect(DatabaseConnection c) : super.connect(c);
+  late final Users users = Users(this);
+  late final Groups groups = Groups(this);
+  late final Notes notes = Notes(this);
+  late final GroupCount groupCount = GroupCount(this);
+  @override
+  Iterable<TableInfo<Table, Object?>> get allTables =>
+      allSchemaEntities.whereType<TableInfo<Table, Object?>>();
+  @override
+  List<DatabaseSchemaEntity> get allSchemaEntities =>
+      [users, groups, notes, groupCount];
+  @override
+  int get schemaVersion => 9;
+  @override
+  DriftDatabaseOptions get options =>
+      const DriftDatabaseOptions(storeDateTimeAsText: true);
+}

examples/migrations_example/lib/tables.dart

@@ -16,4 +16,10 @@ class Users extends Table {
   List<Set<Column>> get uniqueKeys => [
         {name, birthday}
       ];
+
+  @override
+  List<String> get customConstraints => [
+        // This constraint has been added in schema version 9
+        'CHECK (LENGTH(name) < 10)',
+      ];
 }

examples/migrations_example/test/generated/schema.dart

@@ -2,6 +2,7 @@
 //@dart=2.12
 import 'package:drift/drift.dart';
 import 'package:drift/internal/migrations.dart';
+import 'schema_v9.dart' as v9;
 import 'schema_v8.dart' as v8;
 import 'schema_v1.dart' as v1;
 import 'schema_v2.dart' as v2;
@@ -15,6 +16,8 @@ class GeneratedHelper implements SchemaInstantiationHelper {
   @override
   GeneratedDatabase databaseForVersion(QueryExecutor db, int version) {
     switch (version) {
+      case 9:
+        return v9.DatabaseAtV9(db);
       case 8:
         return v8.DatabaseAtV8(db);
       case 1:
@@ -32,7 +35,8 @@ class GeneratedHelper implements SchemaInstantiationHelper {
       case 3:
         return v3.DatabaseAtV3(db);
       default:
-        throw MissingSchemaException(version, const {8, 1, 2, 6, 7, 4, 5, 3});
+        throw MissingSchemaException(
+            version, const {9, 8, 1, 2, 6, 7, 4, 5, 3});
     }
   }
 }

examples/migrations_example/test/generated/schema_v9.dart

@@ -0,0 +1,790 @@
+// GENERATED CODE, DO NOT EDIT BY HAND.
+//@dart=2.12
+import 'package:drift/drift.dart';
+
+class UsersData extends DataClass implements Insertable<UsersData> {
+  final int id;
+  final String name;
+  final DateTime? birthday;
+  final int? nextUser;
+  const UsersData(
+      {required this.id, required this.name, this.birthday, this.nextUser});
+  @override
+  Map<String, Expression> toColumns(bool nullToAbsent) {
+    final map = <String, Expression>{};
+    map['id'] = Variable<int>(id);
+    map['name'] = Variable<String>(name);
+    if (!nullToAbsent || birthday != null) {
+      map['birthday'] = Variable<DateTime>(birthday);
+    }
+    if (!nullToAbsent || nextUser != null) {
+      map['next_user'] = Variable<int>(nextUser);
+    }
+    return map;
+  }
+
+  UsersCompanion toCompanion(bool nullToAbsent) {
+    return UsersCompanion(
+      id: Value(id),
+      name: Value(name),
+      birthday: birthday == null && nullToAbsent
+          ? const Value.absent()
+          : Value(birthday),
+      nextUser: nextUser == null && nullToAbsent
+          ? const Value.absent()
+          : Value(nextUser),
+    );
+  }
+
+  factory UsersData.fromJson(Map<String, dynamic> json,
+      {ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return UsersData(
+      id: serializer.fromJson<int>(json['id']),
+      name: serializer.fromJson<String>(json['name']),
+      birthday: serializer.fromJson<DateTime?>(json['birthday']),
+      nextUser: serializer.fromJson<int?>(json['nextUser']),
+    );
+  }
+  @override
+  Map<String, dynamic> toJson({ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return <String, dynamic>{
+      'id': serializer.toJson<int>(id),
+      'name': serializer.toJson<String>(name),
+      'birthday': serializer.toJson<DateTime?>(birthday),
+      'nextUser': serializer.toJson<int?>(nextUser),
+    };
+  }
+
+  UsersData copyWith(
+          {int? id,
+          String? name,
+          Value<DateTime?> birthday = const Value.absent(),
+          Value<int?> nextUser = const Value.absent()}) =>
+      UsersData(
+        id: id ?? this.id,
+        name: name ?? this.name,
+        birthday: birthday.present ? birthday.value : this.birthday,
+        nextUser: nextUser.present ? nextUser.value : this.nextUser,
+      );
+  @override
+  String toString() {
+    return (StringBuffer('UsersData(')
+          ..write('id: $id, ')
+          ..write('name: $name, ')
+          ..write('birthday: $birthday, ')
+          ..write('nextUser: $nextUser')
+          ..write(')'))
+        .toString();
+  }
+
+  @override
+  int get hashCode => Object.hash(id, name, birthday, nextUser);
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      (other is UsersData &&
+          other.id == this.id &&
+          other.name == this.name &&
+          other.birthday == this.birthday &&
+          other.nextUser == this.nextUser);
+}
+
+class UsersCompanion extends UpdateCompanion<UsersData> {
+  final Value<int> id;
+  final Value<String> name;
+  final Value<DateTime?> birthday;
+  final Value<int?> nextUser;
+  const UsersCompanion({
+    this.id = const Value.absent(),
+    this.name = const Value.absent(),
+    this.birthday = const Value.absent(),
+    this.nextUser = const Value.absent(),
+  });
+  UsersCompanion.insert({
+    this.id = const Value.absent(),
+    this.name = const Value.absent(),
+    this.birthday = const Value.absent(),
+    this.nextUser = const Value.absent(),
+  });
+  static Insertable<UsersData> custom({
+    Expression<int>? id,
+    Expression<String>? name,
+    Expression<DateTime>? birthday,
+    Expression<int>? nextUser,
+  }) {
+    return RawValuesInsertable({
+      if (id != null) 'id': id,
+      if (name != null) 'name': name,
+      if (birthday != null) 'birthday': birthday,
+      if (nextUser != null) 'next_user': nextUser,
+    });
+  }
+
+  UsersCompanion copyWith(
+      {Value<int>? id,
+      Value<String>? name,
+      Value<DateTime?>? birthday,
+      Value<int?>? nextUser}) {
+    return UsersCompanion(
+      id: id ?? this.id,
+      name: name ?? this.name,
+      birthday: birthday ?? this.birthday,
+      nextUser: nextUser ?? this.nextUser,
+    );
+  }
+
+  @override
+  Map<String, Expression> toColumns(bool nullToAbsent) {
+    final map = <String, Expression>{};
+    if (id.present) {
+      map['id'] = Variable<int>(id.value);
+    }
+    if (name.present) {
+      map['name'] = Variable<String>(name.value);
+    }
+    if (birthday.present) {
+      map['birthday'] = Variable<DateTime>(birthday.value);
+    }
+    if (nextUser.present) {
+      map['next_user'] = Variable<int>(nextUser.value);
+    }
+    return map;
+  }
+
+  @override
+  String toString() {
+    return (StringBuffer('UsersCompanion(')
+          ..write('id: $id, ')
+          ..write('name: $name, ')
+          ..write('birthday: $birthday, ')
+          ..write('nextUser: $nextUser')
+          ..write(')'))
+        .toString();
+  }
+}
+
+class Users extends Table with TableInfo<Users, UsersData> {
+  @override
+  final GeneratedDatabase attachedDatabase;
+  final String? _alias;
+  Users(this.attachedDatabase, [this._alias]);
+  late final GeneratedColumn<int> id = GeneratedColumn<int>(
+      'id', aliasedName, false,
+      hasAutoIncrement: true,
+      type: DriftSqlType.int,
+      requiredDuringInsert: false,
+      defaultConstraints:
+          GeneratedColumn.constraintIsAlways('PRIMARY KEY AUTOINCREMENT'));
+  late final GeneratedColumn<String> name = GeneratedColumn<String>(
+      'name', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: false,
+      defaultValue: const Constant('name'));
+  late final GeneratedColumn<DateTime> birthday = GeneratedColumn<DateTime>(
+      'birthday', aliasedName, true,
+      type: DriftSqlType.dateTime, requiredDuringInsert: false);
+  late final GeneratedColumn<int> nextUser = GeneratedColumn<int>(
+      'next_user', aliasedName, true,
+      type: DriftSqlType.int,
+      requiredDuringInsert: false,
+      defaultConstraints:
+          GeneratedColumn.constraintIsAlways('REFERENCES users (id)'));
+  @override
+  List<GeneratedColumn> get $columns => [id, name, birthday, nextUser];
+  @override
+  String get aliasedName => _alias ?? 'users';
+  @override
+  String get actualTableName => 'users';
+  @override
+  Set<GeneratedColumn> get $primaryKey => {id};
+  @override
+  List<Set<GeneratedColumn>> get uniqueKeys => [
+        {name, birthday},
+      ];
+  @override
+  UsersData map(Map<String, dynamic> data, {String? tablePrefix}) {
+    final effectivePrefix = tablePrefix != null ? '$tablePrefix.' : '';
+    return UsersData(
+      id: attachedDatabase.typeMapping
+          .read(DriftSqlType.int, data['${effectivePrefix}id'])!,
+      name: attachedDatabase.typeMapping
+          .read(DriftSqlType.string, data['${effectivePrefix}name'])!,
+      birthday: attachedDatabase.typeMapping
+          .read(DriftSqlType.dateTime, data['${effectivePrefix}birthday']),
+      nextUser: attachedDatabase.typeMapping
+          .read(DriftSqlType.int, data['${effectivePrefix}next_user']),
+    );
+  }
+
+  @override
+  Users createAlias(String alias) {
+    return Users(attachedDatabase, alias);
+  }
+
+  @override
+  List<String> get customConstraints => const ['CHECK (LENGTH(name) < 10)'];
+}
+
+class GroupsData extends DataClass implements Insertable<GroupsData> {
+  final int id;
+  final String title;
+  final bool? deleted;
+  final int owner;
+  const GroupsData(
+      {required this.id,
+      required this.title,
+      this.deleted,
+      required this.owner});
+  @override
+  Map<String, Expression> toColumns(bool nullToAbsent) {
+    final map = <String, Expression>{};
+    map['id'] = Variable<int>(id);
+    map['title'] = Variable<String>(title);
+    if (!nullToAbsent || deleted != null) {
+      map['deleted'] = Variable<bool>(deleted);
+    }
+    map['owner'] = Variable<int>(owner);
+    return map;
+  }
+
+  GroupsCompanion toCompanion(bool nullToAbsent) {
+    return GroupsCompanion(
+      id: Value(id),
+      title: Value(title),
+      deleted: deleted == null && nullToAbsent
+          ? const Value.absent()
+          : Value(deleted),
+      owner: Value(owner),
+    );
+  }
+
+  factory GroupsData.fromJson(Map<String, dynamic> json,
+      {ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return GroupsData(
+      id: serializer.fromJson<int>(json['id']),
+      title: serializer.fromJson<String>(json['title']),
+      deleted: serializer.fromJson<bool?>(json['deleted']),
+      owner: serializer.fromJson<int>(json['owner']),
+    );
+  }
+  @override
+  Map<String, dynamic> toJson({ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return <String, dynamic>{
+      'id': serializer.toJson<int>(id),
+      'title': serializer.toJson<String>(title),
+      'deleted': serializer.toJson<bool?>(deleted),
+      'owner': serializer.toJson<int>(owner),
+    };
+  }
+
+  GroupsData copyWith(
+          {int? id,
+          String? title,
+          Value<bool?> deleted = const Value.absent(),
+          int? owner}) =>
+      GroupsData(
+        id: id ?? this.id,
+        title: title ?? this.title,
+        deleted: deleted.present ? deleted.value : this.deleted,
+        owner: owner ?? this.owner,
+      );
+  @override
+  String toString() {
+    return (StringBuffer('GroupsData(')
+          ..write('id: $id, ')
+          ..write('title: $title, ')
+          ..write('deleted: $deleted, ')
+          ..write('owner: $owner')
+          ..write(')'))
+        .toString();
+  }
+
+  @override
+  int get hashCode => Object.hash(id, title, deleted, owner);
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      (other is GroupsData &&
+          other.id == this.id &&
+          other.title == this.title &&
+          other.deleted == this.deleted &&
+          other.owner == this.owner);
+}
+
+class GroupsCompanion extends UpdateCompanion<GroupsData> {
+  final Value<int> id;
+  final Value<String> title;
+  final Value<bool?> deleted;
+  final Value<int> owner;
+  const GroupsCompanion({
+    this.id = const Value.absent(),
+    this.title = const Value.absent(),
+    this.deleted = const Value.absent(),
+    this.owner = const Value.absent(),
+  });
+  GroupsCompanion.insert({
+    this.id = const Value.absent(),
+    required String title,
+    this.deleted = const Value.absent(),
+    required int owner,
+  })  : title = Value(title),
+        owner = Value(owner);
+  static Insertable<GroupsData> custom({
+    Expression<int>? id,
+    Expression<String>? title,
+    Expression<bool>? deleted,
+    Expression<int>? owner,
+  }) {
+    return RawValuesInsertable({
+      if (id != null) 'id': id,
+      if (title != null) 'title': title,
+      if (deleted != null) 'deleted': deleted,
+      if (owner != null) 'owner': owner,
+    });
+  }
+
+  GroupsCompanion copyWith(
+      {Value<int>? id,
+      Value<String>? title,
+      Value<bool?>? deleted,
+      Value<int>? owner}) {
+    return GroupsCompanion(
+      id: id ?? this.id,
+      title: title ?? this.title,
+      deleted: deleted ?? this.deleted,
+      owner: owner ?? this.owner,
+    );
+  }
+
+  @override
+  Map<String, Expression> toColumns(bool nullToAbsent) {
+    final map = <String, Expression>{};
+    if (id.present) {
+      map['id'] = Variable<int>(id.value);
+    }
+    if (title.present) {
+      map['title'] = Variable<String>(title.value);
+    }
+    if (deleted.present) {
+      map['deleted'] = Variable<bool>(deleted.value);
+    }
+    if (owner.present) {
+      map['owner'] = Variable<int>(owner.value);
+    }
+    return map;
+  }
+
+  @override
+  String toString() {
+    return (StringBuffer('GroupsCompanion(')
+          ..write('id: $id, ')
+          ..write('title: $title, ')
+          ..write('deleted: $deleted, ')
+          ..write('owner: $owner')
+          ..write(')'))
+        .toString();
+  }
+}
+
+class Groups extends Table with TableInfo<Groups, GroupsData> {
+  @override
+  final GeneratedDatabase attachedDatabase;
+  final String? _alias;
+  Groups(this.attachedDatabase, [this._alias]);
+  late final GeneratedColumn<int> id = GeneratedColumn<int>(
+      'id', aliasedName, false,
+      type: DriftSqlType.int,
+      requiredDuringInsert: false,
+      $customConstraints: 'NOT NULL');
+  late final GeneratedColumn<String> title = GeneratedColumn<String>(
+      'title', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: 'NOT NULL');
+  late final GeneratedColumn<bool> deleted = GeneratedColumn<bool>(
+      'deleted', aliasedName, true,
+      type: DriftSqlType.bool,
+      requiredDuringInsert: false,
+      $customConstraints: 'DEFAULT FALSE',
+      defaultValue: const CustomExpression('FALSE'));
+  late final GeneratedColumn<int> owner = GeneratedColumn<int>(
+      'owner', aliasedName, false,
+      type: DriftSqlType.int,
+      requiredDuringInsert: true,
+      $customConstraints: 'NOT NULL REFERENCES users(id)');
+  @override
+  List<GeneratedColumn> get $columns => [id, title, deleted, owner];
+  @override
+  String get aliasedName => _alias ?? 'groups';
+  @override
+  String get actualTableName => 'groups';
+  @override
+  Set<GeneratedColumn> get $primaryKey => {id};
+  @override
+  GroupsData map(Map<String, dynamic> data, {String? tablePrefix}) {
+    final effectivePrefix = tablePrefix != null ? '$tablePrefix.' : '';
+    return GroupsData(
+      id: attachedDatabase.typeMapping
+          .read(DriftSqlType.int, data['${effectivePrefix}id'])!,
+      title: attachedDatabase.typeMapping
+          .read(DriftSqlType.string, data['${effectivePrefix}title'])!,
+      deleted: attachedDatabase.typeMapping
+          .read(DriftSqlType.bool, data['${effectivePrefix}deleted']),
+      owner: attachedDatabase.typeMapping
+          .read(DriftSqlType.int, data['${effectivePrefix}owner'])!,
+    );
+  }
+
+  @override
+  Groups createAlias(String alias) {
+    return Groups(attachedDatabase, alias);
+  }
+
+  @override
+  List<String> get customConstraints => const ['PRIMARY KEY(id)'];
+  @override
+  bool get dontWriteConstraints => true;
+}
+
+class NotesData extends DataClass implements Insertable<NotesData> {
+  final String title;
+  final String content;
+  final String searchTerms;
+  const NotesData(
+      {required this.title, required this.content, required this.searchTerms});
+  @override
+  Map<String, Expression> toColumns(bool nullToAbsent) {
+    final map = <String, Expression>{};
+    map['title'] = Variable<String>(title);
+    map['content'] = Variable<String>(content);
+    map['search_terms'] = Variable<String>(searchTerms);
+    return map;
+  }
+
+  NotesCompanion toCompanion(bool nullToAbsent) {
+    return NotesCompanion(
+      title: Value(title),
+      content: Value(content),
+      searchTerms: Value(searchTerms),
+    );
+  }
+
+  factory NotesData.fromJson(Map<String, dynamic> json,
+      {ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return NotesData(
+      title: serializer.fromJson<String>(json['title']),
+      content: serializer.fromJson<String>(json['content']),
+      searchTerms: serializer.fromJson<String>(json['searchTerms']),
+    );
+  }
+  @override
+  Map<String, dynamic> toJson({ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return <String, dynamic>{
+      'title': serializer.toJson<String>(title),
+      'content': serializer.toJson<String>(content),
+      'searchTerms': serializer.toJson<String>(searchTerms),
+    };
+  }
+
+  NotesData copyWith({String? title, String? content, String? searchTerms}) =>
+      NotesData(
+        title: title ?? this.title,
+        content: content ?? this.content,
+        searchTerms: searchTerms ?? this.searchTerms,
+      );
+  @override
+  String toString() {
+    return (StringBuffer('NotesData(')
+          ..write('title: $title, ')
+          ..write('content: $content, ')
+          ..write('searchTerms: $searchTerms')
+          ..write(')'))
+        .toString();
+  }
+
+  @override
+  int get hashCode => Object.hash(title, content, searchTerms);
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      (other is NotesData &&
+          other.title == this.title &&
+          other.content == this.content &&
+          other.searchTerms == this.searchTerms);
+}
+
+class NotesCompanion extends UpdateCompanion<NotesData> {
+  final Value<String> title;
+  final Value<String> content;
+  final Value<String> searchTerms;
+  const NotesCompanion({
+    this.title = const Value.absent(),
+    this.content = const Value.absent(),
+    this.searchTerms = const Value.absent(),
+  });
+  NotesCompanion.insert({
+    required String title,
+    required String content,
+    required String searchTerms,
+  })  : title = Value(title),
+        content = Value(content),
+        searchTerms = Value(searchTerms);
+  static Insertable<NotesData> custom({
+    Expression<String>? title,
+    Expression<String>? content,
+    Expression<String>? searchTerms,
+  }) {
+    return RawValuesInsertable({
+      if (title != null) 'title': title,
+      if (content != null) 'content': content,
+      if (searchTerms != null) 'search_terms': searchTerms,
+    });
+  }
+
+  NotesCompanion copyWith(
+      {Value<String>? title,
+      Value<String>? content,
+      Value<String>? searchTerms}) {
+    return NotesCompanion(
+      title: title ?? this.title,
+      content: content ?? this.content,
+      searchTerms: searchTerms ?? this.searchTerms,
+    );
+  }
+
+  @override
+  Map<String, Expression> toColumns(bool nullToAbsent) {
+    final map = <String, Expression>{};
+    if (title.present) {
+      map['title'] = Variable<String>(title.value);
+    }
+    if (content.present) {
+      map['content'] = Variable<String>(content.value);
+    }
+    if (searchTerms.present) {
+      map['search_terms'] = Variable<String>(searchTerms.value);
+    }
+    return map;
+  }
+
+  @override
+  String toString() {
+    return (StringBuffer('NotesCompanion(')
+          ..write('title: $title, ')
+          ..write('content: $content, ')
+          ..write('searchTerms: $searchTerms')
+          ..write(')'))
+        .toString();
+  }
+}
+
+class Notes extends Table
+    with TableInfo<Notes, NotesData>, VirtualTableInfo<Notes, NotesData> {
+  @override
+  final GeneratedDatabase attachedDatabase;
+  final String? _alias;
+  Notes(this.attachedDatabase, [this._alias]);
+  late final GeneratedColumn<String> title = GeneratedColumn<String>(
+      'title', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: '');
+  late final GeneratedColumn<String> content = GeneratedColumn<String>(
+      'content', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: '');
+  late final GeneratedColumn<String> searchTerms = GeneratedColumn<String>(
+      'search_terms', aliasedName, false,
+      type: DriftSqlType.string,
+      requiredDuringInsert: true,
+      $customConstraints: '');
+  @override
+  List<GeneratedColumn> get $columns => [title, content, searchTerms];
+  @override
+  String get aliasedName => _alias ?? 'notes';
+  @override
+  String get actualTableName => 'notes';
+  @override
+  Set<GeneratedColumn> get $primaryKey => const {};
+  @override
+  NotesData map(Map<String, dynamic> data, {String? tablePrefix}) {
+    final effectivePrefix = tablePrefix != null ? '$tablePrefix.' : '';
+    return NotesData(
+      title: attachedDatabase.typeMapping
+          .read(DriftSqlType.string, data['${effectivePrefix}title'])!,
+      content: attachedDatabase.typeMapping
+          .read(DriftSqlType.string, data['${effectivePrefix}content'])!,
+      searchTerms: attachedDatabase.typeMapping
+          .read(DriftSqlType.string, data['${effectivePrefix}search_terms'])!,
+    );
+  }
+
+  @override
+  Notes createAlias(String alias) {
+    return Notes(attachedDatabase, alias);
+  }
+
+  @override
+  String get moduleAndArgs =>
+      'fts5(title, content, search_terms, tokenize = "unicode61 tokenchars \'.\'")';
+}
+
+class GroupCountData extends DataClass {
+  final int id;
+  final String name;
+  final DateTime? birthday;
+  final int? nextUser;
+  final int groupCount;
+  const GroupCountData(
+      {required this.id,
+      required this.name,
+      this.birthday,
+      this.nextUser,
+      required this.groupCount});
+  factory GroupCountData.fromJson(Map<String, dynamic> json,
+      {ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return GroupCountData(
+      id: serializer.fromJson<int>(json['id']),
+      name: serializer.fromJson<String>(json['name']),
+      birthday: serializer.fromJson<DateTime?>(json['birthday']),
+      nextUser: serializer.fromJson<int?>(json['nextUser']),
+      groupCount: serializer.fromJson<int>(json['groupCount']),
+    );
+  }
+  @override
+  Map<String, dynamic> toJson({ValueSerializer? serializer}) {
+    serializer ??= driftRuntimeOptions.defaultSerializer;
+    return <String, dynamic>{
+      'id': serializer.toJson<int>(id),
+      'name': serializer.toJson<String>(name),
+      'birthday': serializer.toJson<DateTime?>(birthday),
+      'nextUser': serializer.toJson<int?>(nextUser),
+      'groupCount': serializer.toJson<int>(groupCount),
+    };
+  }
+
+  GroupCountData copyWith(
+          {int? id,
+          String? name,
+          Value<DateTime?> birthday = const Value.absent(),
+          Value<int?> nextUser = const Value.absent(),
+          int? groupCount}) =>
+      GroupCountData(
+        id: id ?? this.id,
+        name: name ?? this.name,
+        birthday: birthday.present ? birthday.value : this.birthday,
+        nextUser: nextUser.present ? nextUser.value : this.nextUser,
+        groupCount: groupCount ?? this.groupCount,
+      );
+  @override
+  String toString() {
+    return (StringBuffer('GroupCountData(')
+          ..write('id: $id, ')
+          ..write('name: $name, ')
+          ..write('birthday: $birthday, ')
+          ..write('nextUser: $nextUser, ')
+          ..write('groupCount: $groupCount')
+          ..write(')'))
+        .toString();
+  }
+
+  @override
+  int get hashCode => Object.hash(id, name, birthday, nextUser, groupCount);
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      (other is GroupCountData &&
+          other.id == this.id &&
+          other.name == this.name &&
+          other.birthday == this.birthday &&
+          other.nextUser == this.nextUser &&
+          other.groupCount == this.groupCount);
+}
+
+class GroupCount extends ViewInfo<GroupCount, GroupCountData>
+    implements HasResultSet {
+  final String? _alias;
+  @override
+  final DatabaseAtV9 attachedDatabase;
+  GroupCount(this.attachedDatabase, [this._alias]);
+  @override
+  List<GeneratedColumn> get $columns =>
+      [id, name, birthday, nextUser, groupCount];
+  @override
+  String get aliasedName => _alias ?? entityName;
+  @override
+  String get entityName => 'group_count';
+  @override
+  String get createViewStmt =>
+      'CREATE VIEW group_count AS SELECT\n    users.*,\n    (SELECT COUNT(*) FROM "groups" WHERE owner = users.id) AS group_count\n  FROM users;';
+  @override
+  GroupCount get asDslTable => this;
+  @override
+  GroupCountData map(Map<String, dynamic> data, {String? tablePrefix}) {
+    final effectivePrefix = tablePrefix != null ? '$tablePrefix.' : '';
+    return GroupCountData(
+      id: attachedDatabase.typeMapping
+          .read(DriftSqlType.int, data['${effectivePrefix}id'])!,
+      name: attachedDatabase.typeMapping
+          .read(DriftSqlType.string, data['${effectivePrefix}name'])!,
+      birthday: attachedDatabase.typeMapping
+          .read(DriftSqlType.dateTime, data['${effectivePrefix}birthday']),
+      nextUser: attachedDatabase.typeMapping
+          .read(DriftSqlType.int, data['${effectivePrefix}next_user']),
+      groupCount: attachedDatabase.typeMapping
+          .read(DriftSqlType.int, data['${effectivePrefix}group_count'])!,
+    );
+  }
+
+  late final GeneratedColumn<int> id =
+      GeneratedColumn<int>('id', aliasedName, false, type: DriftSqlType.int);
+  late final GeneratedColumn<String> name = GeneratedColumn<String>(
+      'name', aliasedName, false,
+      type: DriftSqlType.string);
+  late final GeneratedColumn<DateTime> birthday = GeneratedColumn<DateTime>(
+      'birthday', aliasedName, true,
+      type: DriftSqlType.dateTime);
+  late final GeneratedColumn<int> nextUser = GeneratedColumn<int>(
+      'next_user', aliasedName, true,
+      type: DriftSqlType.int);
+  late final GeneratedColumn<int> groupCount = GeneratedColumn<int>(
+      'group_count', aliasedName, false,
+      type: DriftSqlType.int);
+  @override
+  GroupCount createAlias(String alias) {
+    return GroupCount(attachedDatabase, alias);
+  }
+
+  @override
+  Query? get query => null;
+  @override
+  Set<String> get readTables => const {};
+}
+
+class DatabaseAtV9 extends GeneratedDatabase {
+  DatabaseAtV9(QueryExecutor e) : super(e);
+  DatabaseAtV9.connect(DatabaseConnection c) : super.connect(c);
+  late final Users users = Users(this);
+  late final Groups groups = Groups(this);
+  late final Notes notes = Notes(this);
+  late final GroupCount groupCount = GroupCount(this);
+  @override
+  Iterable<TableInfo<Table, Object?>> get allTables =>
+      allSchemaEntities.whereType<TableInfo<Table, Object?>>();
+  @override
+  List<DatabaseSchemaEntity> get allSchemaEntities =>
+      [users, groups, notes, groupCount];
+  @override
+  int get schemaVersion => 9;
+  @override
+  DriftDatabaseOptions get options =>
+      const DriftDatabaseOptions(storeDateTimeAsText: true);
+}

examples/migrations_example/test/migration_test.dart

@@ -24,7 +24,7 @@ void main() {
   // the schema is correct after the migration.
   // More complex tests ensuring data integrity are written below.
   group('general migration', () {
-    const currentSchema = 7;
+    const currentSchema = Database.latestSchemaVersion;
 
     for (var oldVersion = 1; oldVersion < currentSchema; oldVersion++) {
       group('from v$oldVersion', () {