تصميم نماذج البيانات المتقدمة

تصميم العلاقات بين الكائنات بشكل صحيح.

Class MyApp.Department Extends %Persistent {
  Property Name As %String;
  Relationship Employees As MyApp.Employee [ Cardinality = children, Inverse = Department ];
}
Class MyApp.Employee Extends %Persistent {
  Property Name As %String;
  Relationship Department As MyApp.Department [ Cardinality = one, Inverse = Employees ];
  Index DeptIdx On Department;
}

الفهارس ضرورية لتحسين الأداء.

Class MyApp.Product Extends %Persistent {
  Property Name As %String;
  Property Category As %String;
  Index CatPriceIdx On (Category, Price);
  Index NameTrgm On Name [ Type = bitmap ];
}

نمط Event Sourcing يحفظ كل تغيير كحدث بدلاً من الحالة النهائية.

// تعريف حدث
Class MyApp.Events.OrderEvent Extends %Persistent {
  Property OrderId As %Integer;
  Property EventType As %String; // Created, Updated, Cancelled
  Property EventData As %DynamicObject;
  Property Timestamp As %TimeStamp;
  Index OrderIdx On OrderId;
}

// تسجيل حدث
ClassMethod RegisterEvent(orderId, type, data) {
  Set event = ##class(MyApp.Events.OrderEvent).%New()
  Set event.OrderId = orderId
  Set event.EventType = type
  Set event.EventData = data
  Set event.Timestamp = $ZDT($H,3)
  Do event.%Save()
  
  // تحديث Read Model
  Do ..UpdateProjection(orderId)
}

// إعادة بناء الحالة من الأحداث
ClassMethod RebuildState(orderId) {
  Set state = {}
  &sql(SELECT * FROM MyApp.Events.OrderEvent WHERE OrderId = :orderId ORDER BY Timestamp)
  // تطبيق الأحداث بالترتيب
}