Support excluded in upserts on the Dart API

moor/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.6.0-dev
+
+- Add `DoUpdate.withExcluded` to refer to the excluded row in an upsert clause.
+
 ## 4.5.0
 
 - Add `moorRuntimeOptions.debugPrint` option to control which `print` method is used by moor.

moor/lib/src/dsl/columns.dart

@@ -5,6 +5,15 @@ part of 'dsl.dart';
 abstract class Column<T> extends Expression<T> {
   @override
   final Precedence precedence = Precedence.primary;
+
+  /// The (unescaped) name of this column.
+  ///
+  /// Use [escapedName] to access a name that's escaped in double quotes if
+  /// needed.
+  String get name;
+
+  /// [name], but escaped if it's an sql keyword.
+  String get escapedName => escapeIfNeeded(name);
 }
 
 /// A column that stores int values.

moor/lib/src/dsl/dsl.dart

@@ -3,6 +3,7 @@ import 'dart:typed_data' show Uint8List;
 import 'package:meta/meta.dart';
 import 'package:meta/meta_meta.dart';
 import 'package:moor/moor.dart';
+import 'package:moor/sqlite_keywords.dart';
 
 part 'columns.dart';
 part 'database.dart';

moor/lib/src/runtime/query_builder/schema/column_impl.dart

@@ -7,10 +7,7 @@ const VerificationResult _invalidNull = VerificationResult.failure(
 /// Implementation for a [Column] declared on a table.
 class GeneratedColumn<T> extends Column<T> {
   /// The sql name of this column.
-  final String $name;
+  final String $name; // todo: Remove, replace with `name`
-
-  /// [$name], but escaped if it's an sql keyword.
-  String get escapedName => escapeIfNeeded($name);
 
   /// The name of the table that contains this column
   final String tableName;
@@ -55,6 +52,9 @@ class GeneratedColumn<T> extends Column<T> {
   bool get hasAutoIncrement =>
       _defaultConstraints?.contains('AUTOINCREMENT') == true;
 
+  @override
+  String get name => $name;
+
   /// Used by generated code.
   GeneratedColumn(
     this.$name,

moor/lib/src/runtime/query_builder/statements/insert.dart

@@ -149,7 +149,10 @@ class InsertStatement<T extends Table, D> {
     }
 
     void writeDoUpdate(DoUpdate<T, D> onConflict) {
-      final upsertInsertable = onConflict._createInsertable(table.asDslTable);
+      if (onConflict._usesExcludedTable) {
+        ctx.hasMultipleTables = true;
+      }
+      final upsertInsertable = onConflict._createInsertable(table);
 
       if (!identical(entry, upsertInsertable)) {
         // We run a ON CONFLICT DO UPDATE, so make sure upsertInsertable is
@@ -176,7 +179,9 @@ class InsertStatement<T extends Table, D> {
       for (final target in conflictTarget) {
         if (!first) ctx.buffer.write(', ');
 
-        target.writeInto(ctx);
+        // Writing the escaped name directly because it should not have a table
+        // name in front of it.
+        ctx.buffer.write(target.escapedName);
         first = false;
       }
 
@@ -295,7 +300,8 @@ abstract class UpsertClause<T extends Table, D> {}
 ///
 /// For an example, see [InsertStatement.insert].
 class DoUpdate<T extends Table, D> extends UpsertClause<T, D> {
-  final Insertable<D> Function(T old) _creator;
+  final Insertable<D> Function(T old, T excluded) _creator;
+  final bool _usesExcludedTable;
 
   /// An optional list of columns to serve as an "conflict target", which
   /// specifies the uniqueness constraint that will trigger the upsert.
@@ -303,12 +309,32 @@ class DoUpdate<T extends Table, D> extends UpsertClause<T, D> {
   /// By default, the primary key of the table will be used.
   final List<Column>? target;
 
+  /// Creates a `DO UPDATE` clause.
+  ///
+  /// The [update] function will be used to construct an [Insertable] used to
+  /// update an old row that prevented an insert.
+  /// If you need to refer to both the old row and the row that would have
+  /// been inserted, use [DoUpdate.withExcluded].
+  ///
   /// For an example, see [InsertStatement.insert].
   DoUpdate(Insertable<D> Function(T old) update, {this.target})
-      : _creator = update;
+      : _creator = ((old, _) => update(old)),
+        _usesExcludedTable = false;
 
-  Insertable<D> _createInsertable(T table) {
+  /// Creates a `DO UPDATE` clause.
-    return _creator(table);
+  ///
+  /// The [update] function will be used to construct an [Insertable] used to
+  /// update an old row that prevented an insert.
+  /// It can refer to the values from the old row in the first parameter and
+  /// to columns in the row that couldn't be inserted with the `excluded`
+  /// parameter.
+  ///
+  /// For an example, see [InsertStatement.insert].
+  DoUpdate.withExcluded(this._creator, {this.target})
+      : _usesExcludedTable = true;
+
+  Insertable<D> _createInsertable(TableInfo<T, D> table) {
+    return _creator(table.asDslTable, table.createAlias('excluded').asDslTable);
   }
 }
 

moor/pubspec.yaml

@@ -1,6 +1,6 @@
 name: moor
 description: Moor is a safe and reactive persistence library for Dart applications
-version: 4.5.0
+version: 4.6.0-dev
 repository: https://github.com/simolus3/moor
 homepage: https://moor.simonbinder.eu/
 issue_tracker: https://github.com/simolus3/moor/issues

moor/test/insert_test.dart

@@ -266,6 +266,24 @@ void main() {
     expect(id, 3);
   });
 
+  test('can access excluded row in upsert', () async {
+    await db.into(db.todosTable).insert(
+          TodosTableCompanion.insert(content: 'content'),
+          onConflict: DoUpdate.withExcluded(
+            (old, excluded) => TodosTableCompanion.custom(
+              content: old.content + excluded.content,
+            ),
+          ),
+        );
+
+    verify(executor.runInsert(
+      'INSERT INTO todos (content) VALUES (?) '
+      'ON CONFLICT(id) DO UPDATE '
+      'SET content = todos.content || excluded.content',
+      ['content'],
+    ));
+  });
+
   test('applies implicit type converter', () async {
     await db.into(db.categories).insert(CategoriesCompanion.insert(
           description: 'description',

moor/test/integration_tests/insert_integration_test.dart

@@ -26,6 +26,27 @@ void main() {
     expect(row.description, 'changed description');
   });
 
+  test('insert with DoUpdate and excluded row', () async {
+    await db.into(db.categories).insert(
+        CategoriesCompanion.insert(description: 'original description'));
+
+    var row = await db.select(db.categories).getSingle();
+
+    await db.into(db.categories).insert(
+        CategoriesCompanion(
+          id: Value(row.id),
+          description: const Value('new description'),
+        ),
+        onConflict: DoUpdate.withExcluded(
+          (old, excluded) => CategoriesCompanion.custom(
+              description:
+                  old.description + const Constant(' ') + excluded.description),
+        ));
+
+    row = await db.select(db.categories).getSingle();
+    expect(row.description, 'original description new description');
+  });
+
   test('returning', () async {
     final entry = await db.into(db.categories).insertReturning(
         CategoriesCompanion.insert(description: 'Description'));