moving transaction savepoint statements to NoTransactionDelegate

drift/lib/src/runtime/executor/helpers/delegates.dart

@@ -3,6 +3,12 @@ import 'dart:async' show FutureOr;
 import 'package:drift/drift.dart';
 import 'package:drift/src/runtime/executor/helpers/results.dart';
 
+String _defaultSavepoint(int depth) => 'SAVEPOINT s$depth';
+
+String _defaultRelease(int depth) => 'RELEASE s$depth';
+
+String _defaultRollbackToSavepoint(int depth) => 'ROLLBACK TO s$depth';
+
 /// An interface that supports sending database queries. Used as a backend for
 /// drift.
 ///
@@ -132,6 +138,18 @@ class NoTransactionDelegate extends TransactionDelegate {
   /// database engine.
   final String rollback;
 
+  /// The statement that will create a savepoint for a given depth of a transaction
+  /// on this database engine.
+  final String Function(int depth) savepoint;
+
+  /// The statement that will release a savepoint for a given depth of a transaction
+  /// on this database engine.
+  final String Function(int depth) release;
+
+  /// The statement that will perform a rollback to a savepoint for a given depth
+  /// of a transaction on this database engine.
+  final String Function(int depth) rollbackToSavepoint;
+
   /// Construct a transaction delegate indicating that native transactions
   /// aren't supported and need to be emulated by issuing statements and
   /// locking the database.
@@ -139,6 +157,9 @@ class NoTransactionDelegate extends TransactionDelegate {
     this.start = 'BEGIN TRANSACTION',
     this.commit = 'COMMIT TRANSACTION',
     this.rollback = 'ROLLBACK TRANSACTION',
+    this.savepoint = _defaultSavepoint,
+    this.release = _defaultRelease,
+    this.rollbackToSavepoint = _defaultRollbackToSavepoint,
   });
 }
 

drift/lib/src/runtime/executor/helpers/engines.dart

@@ -187,11 +187,9 @@ class _StatementBasedTransactionExecutor extends _TransactionExecutor {
   _StatementBasedTransactionExecutor.nested(
       _StatementBasedTransactionExecutor this._parent, int depth)
       : _delegate = _parent._delegate,
-        _startCommand = 'SAVEPOINT s$depth',
-        _commitCommand = _parent._db.dialect == SqlDialect.mariadb
-            ? 'RELEASE SAVEPOINT s$depth' : 'RELEASE s$depth',
-        _rollbackCommand = _parent._db.dialect == SqlDialect.mariadb
-            ? 'ROLLBACK TO SAVEPOINT s$depth' : 'ROLLBACK TO s$depth',
+        _startCommand = _parent._delegate.savepoint(depth),
+        _commitCommand = _parent._delegate.release(depth),
+        _rollbackCommand = _parent._delegate.rollbackToSavepoint(depth),
         super(_parent._db);
 
   @override