Batched insert statements

Closes #15

moor/lib/src/runtime/executor/executor.dart

@@ -1,6 +1,8 @@
 import 'dart:async';
 
+import 'package:collection/collection.dart';
 import 'package:moor/src/runtime/database.dart';
+import 'package:moor/src/utils/hash.dart';
 
 /// A query executor is responsible for executing statements on a database and
 /// return their results in a raw form.
@@ -36,10 +38,46 @@ abstract class QueryExecutor {
   /// statement will be ignored.
   Future<void> runCustom(String statement);
 
+  /// Prepares the [statements] and then executes each one with all of the
+  /// [BatchedStatement.variables].
+  Future<void> runBatched(List<BatchedStatement> statements);
+
   /// Starts a [TransactionExecutor].
   TransactionExecutor beginTransaction();
 }
 
+/// A statement that should be executed in a batch. Used internally by moor.
+class BatchedStatement {
+  static const _nestedListEquality = ListEquality(ListEquality());
+
+  /// The raw sql that needs to be executed
+  final String sql;
+
+  /// The variables to be used for the statement. Each entry holds a list of
+  /// variables that should be bound to the [sql] statement.
+  final List<List<dynamic>> variables;
+
+  BatchedStatement(this.sql, this.variables);
+
+  @override
+  int get hashCode {
+    return $mrjf($mrjc(sql.hashCode, const ListEquality().hash(variables)));
+  }
+
+  @override
+  bool operator ==(other) {
+    return identical(this, other) ||
+        (other is BatchedStatement &&
+            other.sql == sql &&
+            _nestedListEquality.equals(variables, other.variables));
+  }
+
+  @override
+  String toString() {
+    return 'BatchedStatement($sql, $variables)';
+  }
+}
+
 /// A [QueryExecutor] that runs multiple queries atomically.
 abstract class TransactionExecutor extends QueryExecutor {
   /// Completes the transaction. No further queries may be sent to to this

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

@@ -26,12 +26,18 @@ class InsertStatement<DataClass> {
   /// If the table contains an auto-increment column, the generated value will
   /// be returned.
   Future<int> insert(DataClass entity) async {
-    if (!table.validateIntegrity(entity, true)) {
-      throw InvalidDataException(
-          'Invalid data: $entity cannot be written into ${table.$tableName}');
-    }
+    _validateIntegrity(entity);
+    final ctx = _createContext(entity, _orReplace);
 
-    final map = table.entityToSql(entity)
+    return await database.executor.doWhenOpened((e) async {
+      final id = await database.executor.runInsert(ctx.sql, ctx.boundVariables);
+      database.markTablesUpdated({table});
+      return id;
+    });
+  }
+
+  GenerationContext _createContext(DataClass entry, bool replace) {
+    final map = table.entityToSql(entry)
       ..removeWhere((_, value) => value == null);
 
     final ctx = GenerationContext(database);
@@ -56,15 +62,51 @@ class InsertStatement<DataClass> {
     }
 
     ctx.buffer.write(')');
-
-    return await database.executor.doWhenOpened((e) async {
-      final id = await database.executor.runInsert(ctx.sql, ctx.boundVariables);
-      database.markTablesUpdated({table});
-      return id;
-    });
+    return ctx;
   }
 
-  // TODO insert multiple values
+  void _validateIntegrity(DataClass d) {
+    if (d == null) {
+      throw InvalidDataException(
+          'Cannot writee null row into ${table.$tableName}');
+    }
+    if (!table.validateIntegrity(d, true)) {
+      throw InvalidDataException(
+          'Invalid data: $d cannot be written into ${table.$tableName}');
+    }
+  }
+
+  /// Inserts all [rows] into the table.
+  ///
+  /// All fields in a row that don't have a default value or auto-increment
+  /// must be set and non-null. Otherwise, an [InvalidDataException] will be
+  /// thrown.
+  /// When a row with the same primary or unique key already exists in the
+  /// database, the insert will fail. Use [orReplace] to replace rows that
+  /// already exist.
+  Future<void> insertAll(List<DataClass> rows, {bool orReplace}) async {
+    final statements = <String, List<GenerationContext>>{};
+
+    // Not every insert has the same sql, as fields which are set to null are
+    // not included. So, we have a map for sql -> list of variables which we can
+    // then turn into prepared statements
+    for (var row in rows) {
+      _validateIntegrity(row);
+
+      final ctx = _createContext(row, orReplace);
+      statements.putIfAbsent(ctx.sql, () => []).add(ctx);
+    }
+
+    final batchedStatements = statements.entries.map((e) {
+      final vars = e.value.map((context) => context.boundVariables).toList();
+      return BatchedStatement(e.key, vars);
+    }).toList(growable: false);
+
+    await database.executor.doWhenOpened((e) async {
+      await e.runBatched(batchedStatements);
+    });
+    database.markTablesUpdated({table});
+  }
 
   /// Updates the row with the same primary key in the database or creates one
   /// if it doesn't exist.

moor/test/insert_test.dart

@@ -35,6 +35,29 @@ void main() {
         [113, 'Done']));
   });
 
+  test('runs bulk inserts', () async {
+    await db.into(db.todosTable).insertAll([
+      TodoEntry(content: 'a'),
+      TodoEntry(title: 'title', content: 'b'),
+      TodoEntry(title: 'title', content: 'c'),
+    ]);
+
+    final insertSimple = 'INSERT INTO todos (content) VALUES (?)';
+    final insertTitle = 'INSERT INTO todos (title, content) VALUES (?, ?)';
+
+    verify(executor.runBatched([
+      BatchedStatement(insertSimple, [
+        ['a']
+      ]),
+      BatchedStatement(insertTitle, [
+        ['title', 'b'],
+        ['title', 'c']
+      ]),
+    ]));
+
+    verify(streamQueries.handleTableUpdates({db.todosTable}));
+  });
+
   test('notifies stream queries on inserts', () async {
     await db.into(db.users).insert(User(
           name: 'User McUserface',
@@ -45,7 +68,7 @@ void main() {
     verify(streamQueries.handleTableUpdates({db.users}));
   });
 
-  test('enforces data integrety', () {
+  test('enforces data integrity', () {
     expect(
       db.into(db.todosTable).insert(
             TodoEntry(

moor_flutter/lib/moor_flutter.dart

@@ -57,6 +57,20 @@ abstract class _DatabaseOwner extends QueryExecutor {
     _log(statement, null);
     return db.execute(statement);
   }
+
+  @override
+  Future<void> runBatched(List<BatchedStatement> statements) async {
+    final batch = db.batch();
+
+    for (var statement in statements) {
+      for (var boundVariables in statement.variables) {
+        _log(statement.sql, boundVariables);
+        batch.execute(statement.sql, boundVariables);
+      }
+    }
+
+    await batch.commit(noResult: true);
+  }
 }
 
 /// A query executor that uses sqflite internally.
@@ -115,10 +129,7 @@ class FlutterQueryExecutor extends _DatabaseOwner {
 
   SqlExecutor _migrationExecutor(s.Database db) {
     return (sql) {
-      if (logStatements) {
-        _log(sql);
-      }
-
+      _log(sql);
       db.execute(sql);
     };
   }