From c5c8dc7d6d94f0af2e9a67b50a8765544625dc83 Mon Sep 17 00:00:00 2001
From: Simon Binder <oss@simonbinder.eu>
Date: Tue, 7 Jan 2020 11:31:35 +0100
Subject: [PATCH] Support delete statements in batches

Closes #325
---
 moor/CHANGELOG.md                   |  1 +
 moor/lib/src/runtime/api/batch.dart | 10 ++++++++++
 moor/test/batch_test.dart           |  6 ++++++
 3 files changed, 17 insertions(+)

diff --git a/moor/CHANGELOG.md b/moor/CHANGELOG.md
index 0b7390db..924942a4 100644
--- a/moor/CHANGELOG.md
+++ b/moor/CHANGELOG.md
@@ -13,6 +13,7 @@
   To create them in `onUpgrade`, use the new `createIndex` and `createTrigger` functions on a `Migrator`.
 - Support for moor-file queries that run on initialization ([#280](https://github.com/simolus3/moor/issues/280))
   Declare them like this `@create: INSERT INTO users VALUES ('default', 'user')`
+- Support deletes in batches ([#325](https://github.com/simolus3/moor/issues/325))
   
 ## 2.2.0
 
diff --git a/moor/lib/src/runtime/api/batch.dart b/moor/lib/src/runtime/api/batch.dart
index 75602e78..8f2e7ecd 100644
--- a/moor/lib/src/runtime/api/batch.dart
+++ b/moor/lib/src/runtime/api/batch.dart
@@ -94,6 +94,16 @@ class Batch {
     }
   }
 
+  /// Deletes all rows from [table] matching the provided [filter].
+  ///
+  /// See also:
+  ///  - [QueryEngine.delete]
+  void delete<T extends Table, D extends DataClass>(TableInfo<T, D> table,
+      Expression<bool, BoolType> Function(T tbl) filter) {
+    final stmt = DeleteStatement(_engine, table)..where(filter);
+    _addContext(stmt.constructQuery());
+  }
+
   void _addContext(GenerationContext ctx) {
     final sql = ctx.sql;
     final variableSet = _createdStatements.putIfAbsent(sql, () => []);
diff --git a/moor/test/batch_test.dart b/moor/test/batch_test.dart
index 997ee71a..d7dfdc56 100644
--- a/moor/test/batch_test.dart
+++ b/moor/test/batch_test.dart
@@ -37,6 +37,8 @@ void main() {
         CategoriesCompanion(id: Value(1), description: Value('new1')),
         CategoriesCompanion(id: Value(2), description: Value('new2')),
       ]);
+
+      b.delete(db.categories, (_) => const Constant(true));
     });
 
     final transaction = executor.transactions;
@@ -67,6 +69,10 @@ void main() {
           ['new2', 2],
         ],
       ),
+      BatchedStatement(
+        'DELETE FROM categories WHERE 1;',
+        [[]],
+      ),
     ]));
   });