Find and generate update rules during builds

moor/test/data/tables/custom_tables.g.dart

@@ -1272,6 +1272,10 @@ abstract class _$CustomTablesDb extends GeneratedDatabase {
         mytable,
         email
       ];
+  @override
+  StreamQueryUpdateRules get streamUpdateRules => const StreamQueryUpdateRules([
+        WritePropagation('config', {'with_defaults'})
+      ]);
 }
 
 class TableValuedResult {

moor_generator/lib/src/analyzer/moor/entity_handler.dart

@@ -33,8 +33,7 @@ class EntityHandler extends BaseAnalyzer {
         entity.references.clear();
         _handleMoorDeclaration<MoorTableDeclaration>(entity, _tables);
       } else if (entity is MoorTrigger) {
-        entity.on = null;
+        entity.clearResolvedReferences();
-        entity.bodyReferences.clear();
 
         final node =
             _handleMoorDeclaration(entity, _triggers) as CreateTriggerStatement;
@@ -43,7 +42,9 @@ class EntityHandler extends BaseAnalyzer {
         _lint(node, entity.displayName);
 
         // find additional tables that might be referenced in the body
+
         entity.bodyReferences.addAll(_findTables(node.action));
+        entity.bodyUpdates.addAll(_findUpdatedTables(node.action));
       } else if (entity is MoorIndex) {
         entity.table = null;
 
@@ -72,6 +73,12 @@ class EntityHandler extends BaseAnalyzer {
     return tablesFinder.foundTables.map(mapper.tableToMoor);
   }
 
+  Iterable<MoorTable> _findUpdatedTables(AstNode node) {
+    final finder = UpdatedTablesVisitor();
+    node.acceptWithoutArg(finder);
+    return finder.writtenTables.map(mapper.tableToMoor);
+  }
+
   AstNode _handleMoorDeclaration<T extends MoorDeclaration>(
     HasDeclaration e,
     Map<AstNode, HasDeclaration> map,

moor_generator/lib/src/backends/build/generators/dao_generator.dart

@@ -24,9 +24,8 @@ class DaoGenerator extends Generator implements BaseGenerator {
       for (final table in dao.tables) {
         final infoType = table.tableInfoName;
         final getterName = table.dbGetterName;
-        classScope
+        classScope.leaf().write(
-            .leaf()
+            '$infoType get $getterName => attachedDatabase.$getterName;\n');
-            .write('$infoType get $getterName => db.$getterName;\n');
       }
 
       final writtenMappingMethods = <String>{};

moor_generator/lib/src/model/trigger.dart

@@ -14,6 +14,7 @@ class MoorTrigger implements MoorSchemaEntity {
   ///
   /// This field can be null in case the table wasn't resolved.
   MoorTable on;
+  List<MoorTable> bodyUpdates = [];
   List<MoorTable> bodyReferences = [];
 
   String _create;
@@ -28,6 +29,12 @@ class MoorTrigger implements MoorSchemaEntity {
     );
   }
 
+  void clearResolvedReferences() {
+    on = null;
+    bodyUpdates.clear();
+    bodyReferences.clear();
+  }
+
   @override
   Iterable<MoorSchemaEntity> get references => {on, ...bodyReferences};
 

moor_generator/lib/src/services/find_stream_update_rules.dart

@@ -0,0 +1,23 @@
+import 'package:moor/moor.dart';
+import 'package:moor_generator/moor_generator.dart';
+
+class FindStreamUpdateRules {
+  final Database db;
+
+  FindStreamUpdateRules(this.db);
+
+  StreamQueryUpdateRules identifyRules() {
+    final rules = <UpdateRule>[];
+
+    for (final trigger in db.entities.whereType<MoorTrigger>()) {
+      rules.add(
+        WritePropagation(
+          trigger.on.sqlName,
+          trigger.bodyUpdates.map((t) => t.sqlName).toSet(),
+        ),
+      );
+    }
+
+    return StreamQueryUpdateRules(rules);
+  }
+}

moor_generator/lib/src/writer/database_writer.dart

@@ -1,4 +1,6 @@
+import 'package:moor/moor.dart';
 import 'package:moor_generator/moor_generator.dart';
+import 'package:moor_generator/src/services/find_stream_update_rules.dart';
 import 'package:moor_generator/src/utils/string_escaper.dart';
 import 'package:moor_generator/writer.dart';
 import 'package:recase/recase.dart';
@@ -103,7 +105,33 @@ class DatabaseWriter {
 
         return entityGetters[e];
       }).join(', '))
-      // close list literal, getter and finally the class
+      // close list literal and allSchemaEntities getter
-      ..write('];\n}');
+      ..write('];\n');
+
+    final updateRules = FindStreamUpdateRules(db).identifyRules();
+    if (updateRules.rules.isNotEmpty) {
+      schemaScope
+        ..write('@override\nStreamQueryUpdateRules get streamUpdateRules => ')
+        ..write('const StreamQueryUpdateRules([');
+
+      var isFirst = true;
+      for (final rule in updateRules.rules) {
+        if (!isFirst) {
+          schemaScope.write(', ');
+        }
+        isFirst = false;
+
+        if (rule is WritePropagation) {
+          final updateNames = rule.updates.map(asDartLiteral).join(', ');
+          schemaScope.write('WritePropagation('
+              '${asDartLiteral(rule.onTable)}, {$updateNames})');
+        }
+      }
+
+      schemaScope.write(']);');
+    }
+
+    // close the class
+    schemaScope.write('}');
   }
 }