domain-driven-design

Pagination in a Rich Domain Model

I use rich domain model in my app. The basic ideas were taken there. For example I have User and Comment entities. They are defined as following: <?php class Model_User extends Model_Abstract { public function getComments() { /** * @var Model_Mapper_Db_Comment */ $mapper = $this->getMapper(); ...

Service Layer are repeating my Repositories

Hi all, I'm developing an application using asp.net mvc, NHibernate and DDD. I have a service layer that are used by controllers of my application. Everything are using Unity to inject dependencies (ISessionFactory in repositories, repositories in services and services in controllers) and works fine. But, it's very common I need a met...

How should I structure my repository classes?

I am new to DDD. In my mini-project, I have a structure that looks like this (different from the actual names): EntryClassificationGroup EntryClassification Entry EntryType Should I have just one repository class for all these 4 entities, since they are all related? Or should I have individual repositories for each one? ...

How to avoid having very large objects with Domain Driven Design

We are following Domain Driven Design for the implementation of a large website. However by putting the behaviour on the domain objects we are ending up with some very large classes. For example on our WebsiteUser object, we have many many methods - e.g. dealing with passwords, order history, refunds, customer segmentation. All of the...

DDD and IOC Containers

Hi Im fairly new with DDD and Im trying to use IOC in order to loosen up my tightly coupled layers :) My C# web application consists of a UI, domain and persistence layer. My persistence layer references my domain layer and contains my concrete repository implementations and nhibernate mappings. Currently my UI references my domain lay...

Design of Business Layer

Hi, We are currently revamping our architecture and design of application. We have just completed design of Data Access Layer which is generic in the sense that it works using XML and reflection to persist data. Any ways now we are in the phase of designing business layer. We have read some books related to Enterprise Architecture and ...

Should an event-sourced aggregate root have access to the event sourcing repository?

I'm working on an event-sourced CQRS implementation, using DDD in the application / domain layer. I have an object model that looks like this: public class Person : AggregateRootBase { private Guid? _bookingId; public Person(Identification identification) { Apply(new PersonCreatedEvent(identification)); } ...

What makes my code DDD (domain-driven design) qualified?

Hi All, I'm new to DDD and am thinking about using this design technique in my project. However, what strikes me about DDD is that how basic the idea is. Unlike other design techniques such as MVC and TDD, it doesn't seems to contain any ground breaking ideas. For example, I'm sure some of you will have the same feeling that the idea ...

Guidelines for solution source code organisation(OO/DDD)

I'm starting on my first business project (.NET) and am trying to follow DDD principles. Are there any guidelines or common patterns for orgaining source code and namespaces? For example, do your domain objects go in a namespace MyProject.Domain or whatever? Would you separate the concrete implementations and the interfaces? In differen...

How do I implement repository pattern and unit of work when dealing with multiple data stores?

I have a unique situation where I am building a DDD based system that needs to access both Active Directory and a SQL database as persistence. Initially this wasnt a problem because our design was setup where we had a unit of work that looked like this: public interface IUnitOfWork { void BeginTransaction() void Commit() } and o...

CQRS and email notification

Reading up on CQRS there is a lot of talk of email notification - i'm wondering where to get the data from. Imagine a senario where one user invites other users to an event. To inform a user that he has been invitet to an event, he is send an email. The concrete mecanics might go like this: A "CreateEvent" command with an associated...

How to handle set based consistency validation in CQRS?

I have a fairly simple domain model involving a list of Facility aggregate roots. Given that I'm using CQRS and an event-bus to handle events raised from the domain, how could you handle validation on sets? For example, say I have the following requirement: Facility's must have a unique name. Since I'm using an eventually consiste...

Creating Domain Model

Hi, I have created a use case of a small application and now I have to create a Domain Model of that use cases of the application and which functions will be implemented in this application. I have no previous experience in Domain Modeling and UML, please suggest me steps to create the domain model or any suggestions, Do I have to have a...

Should i use partial classes as business layer when using entity framework?

I am working on a project using entity framework. Is it okay to use partial classes of the EF generated classes as the business layer. I am begining to think that this is how EF is intended to be used. I have attempted to use a DTO pattern and soon realized that i am just creating a bunch of mapping classes that is duplicating my effort...

In CQRS (event-sourced), do you need a global sequence counter in the event store?

In trying to get my head around CQRS (and DDD in general) I have come across situations when two events occur on different aggregates but the order of them has domain meaning. If so then they could happen so close together that a timestamp (as used by the sample implementations I have seen) cannot differentiate them, meaning the event s...

Domain driven design value object, how to ensure a unique value

Hi, I am building a questionnaire creator. A questionnaire consists of sections, sections consist of pages and pages consist of questions. Questionnaire is the aggregate root. Sections, pages and questions can have what are called shortcodes which should be unique within a questionnaire (but not unique within the database hence they ar...

domain modeling naming problem

Hello There are some simple entities in an application (e.g containing only id and title) which rarely change and are being referenced by the more complex entities of the application. These are usually entities such as Country, City, Language etc. How are these called? I've used the following names for those in the past but I'm not sur...

How to retrieve Aggregate objects?

In DDD, Repository takes care of saving and retrieving domain objects and also serves as collection of Aggregate Roots. My question is how do you retrieve the information for those child entities (let's say from DB) of an Aggregate where basic rule is Repository should just hold collection of Aggregate Roots (parent object) and not child...

DDD and MVC Models hold ID of separate entity or the entity itself?

If you have an Order that references a customer, does the model include the ID of the customer or a copy of the customer object like a value object (thinking DDD)? I would like to do ths: public class Order { public int ID {get;set;} public Customer customer {get;set;} ... } right now I do this: public class Order { ...

Repository, Service or Domain object - where does logic belong?

Take this simple, contrived example: UserRepository.GetAllUsers(); UserRepository.GetUserById(); Inevitably, I will have more complex "queries", such as: //returns users where active=true, deleted=false, and confirmed = true GetActiveUsers(); I'm having trouble determining where the responsibility of the repository ends. GetActiveU...