Domain-driven design (DDD) is an approach to develop software for complex needs by connecting the implementation to an evolving model.
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252 views
Distributed application using RabbitMQ
I am on my way to create an application with 4 bounded context using CQRS & event sourcing.
In order to make these bounded context talk to each other I was planning on using Rabbit MQ.
My ...
2
votes
1answer
393 views
CQRS + Event Sourcing: (is it correct that) Commands are generally communicated point-to-point, while Domain Events are communicated through pub/sub?
Didn't know how to shorten that title.
I'm basically trying to wrap my head around the concept of CQRS ( http://en.wikipedia.org/wiki/Command-query_separation) and related concepts.
Although CQRS ...
4
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2answers
754 views
DDD, Saga & Event-sourcing: Can a Compensate Action simply be a delete on the event store?
I realize the above question probably raises a few 'what??'s, but let me try to explain :
I'm trying to wrap my head on a couple of related concepts, basically the Saga-pattern ( ...
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2answers
448 views
Are Persistence-Ignorant objects able to implement lazy loading?
Persistence Ignorance is an application of single responsibility principle, which in practice means that Domain Objects (DO) shouldn't contain code related to persistence, instead they should only ...
19
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3answers
10k views
Programming SOLID Principles
Over time I could understand two parts of SOLID – the “S” and “O”.
“O” – I learned Open Closed Principle with the help of Inheritance and Strategy Pattern.
“S” – I learned Single Responsibility ...
3
votes
2answers
613 views
Should this code/logic be included in Business Objects class or a separate class?
I have created a small application which has a three tier architecture and I have business object classes to represent entities such as User, Orders, UserType etc. In these classes I have methods that ...
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vote
2answers
867 views
What is a best practice tier structure of a Java EE 6/7 application?
I was attempting to find a best practice for modeling the tiers in a Java EE application yesterday and couldn't come up with anything current. In the past, say java 1.4, it was four tiers:
...
2
votes
2answers
442 views
Equivalent of Domain Driven Design for functional programming languages
I really love the idea of domain driven design, however, as I'm learning Go, I'm wondering if there's the equivalent of DDD that's aimed at an effectively more functional language?
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2answers
181 views
Designing a hierarchical structure with lots of reads and writes?
I am in the process of working on a video on demand system part of it involves the management of a hierarchical tree structure (think windows explorer) which allows users to upload videos, move ...
7
votes
2answers
240 views
How to make this design closer to proper DDD?
I've read about DDD for days now and need help with this sample design. All the rules of DDD make me very confused to how I'm supposed to build anything at all when domain objects are not allowed to ...
2
votes
2answers
348 views
Web workflow solution - how should I approach the design?
We've been tasked with creating a web based workflow tool to track change management. It has a single workflow with multiple synchronous tasks for the most part, but branch out at a point to tasks ...
0
votes
1answer
287 views
DDD identifying aggregate root
I am designing the a web application using domain driven design.I have following scenario:
Each applicationGroup can have one Application and each application can have multiple configuration.I am ...
2
votes
2answers
237 views
DDD: Developing the Domain Model alone
In DDD examples it seems the common method for developing the domain model is to sit with domain experts and iterate over versions of the model, say on a whiteboard, continually modifying it and ...
3
votes
3answers
317 views
Scrum, DDD, and front-end development in an enterprise environment
So, I've been working for a bank for the past 4 years. My main responsibility has been online banking. Over the past year, we've been implementing the scrum methodology. We've also changed to domain ...
7
votes
3answers
773 views
Validation and authorization in layered architecture
I know you are thinking (or maybe yelling), "not another question asking where validation belongs in a layered architecture?!?" Well, yes, but hopefully this will be a little bit of a different take ...
6
votes
3answers
1k views
When should an Aggregate Root contain another AR (and when should it not)
Let me begin by first apologizing for the length of the post, but I really wanted to convey as much detail up-front so I don't take your time going back and forth in comments.
I am designing an ...
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vote
1answer
222 views
Drawback of implementing DDD service as static class?
Can Services in a domain-driven design be implemented as C# static class? What are the drawbacks of this choice? Can it be implemented as a non-singleton non-static class?
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votes
4answers
182 views
How to decide whether to implement an operation as Entity operation vs Service operation in Domain Driven Design?
I am reading Evans's Domain Driven Design. The book says that there are entity and there are services. If I were to implement an operation, how to decide whether I should add it as a method on an ...
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5answers
2k views
Application layer vs domain layer?
I am reading Domain-Driven Design by Evans and I am at the part discussing the layered architecture. I just realized that application and domain layers are different and should be separate. In the ...
16
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5answers
653 views
Do ORMs enable the creation of rich domain models?
After using Hibernate on most of my projects for about 8 years, I've landed on a company that discourages its use and wants applications to only interact with the DB through stored procedures.
After ...
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vote
1answer
281 views
DDD and validation of aggregate root
Suppose an aggregate root : MailConfiguration (wrapping an AddressPart object). The AddressPart object is a simple immutable value object with some fields like senderAdress, recipentAddress (to make ...
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vote
1answer
69 views
Question about state and domain objects
Suppose I create a domain object called UserAdministration, if i have a method called CreateUser how would i pass state to this method, would I create properties on the UserAdministration object and ...
2
votes
1answer
466 views
Forcing aggregate root child access through the aggregate root alone
Context
I'm developing an application using a Domain Driven Design approach. I want to use a design pattern wherever appropriate and apply all SOLID principles.
Scenario
I have an order and I want ...
3
votes
1answer
299 views
what does “domain” mean when referring to DDD
What does the word domain mean regarding driven design/development?
Not in terms of semantics or a scholarly definition but in terms of how it modifies processes or philosophies?
I was reading a ...
3
votes
2answers
250 views
How should I include third-party models in my domain model?
I'm currently trying to design a little application using Domain Driven Design but I'm afraid I don't really get the concept yet. Let me try to explain this as clearly as possible.
public interface ...
5
votes
3answers
195 views
Computed Values and Simple Reads - A nagging pain for my Domain Driven Designs!
The problem I continually face is how to deal with computed values driven by domain logic while still working efficiently against the data store.
Example:
I'm returning a list of Products from my ...
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votes
6answers
6k views
Difference between a service class and a Helper class
I would like to know what differentiates a Service class from a utility class or a helper class?
A class only with underlying methods calls the dao's is a service? Doesn't the usage of Helper ...
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vote
1answer
214 views
Is it ok to call external services or database inside the entity
I have "logic engine" which executes set of user configured steps. These steps are saved in the database as "Step" entities. The engine gets the first step and then executes steps until there are no ...
2
votes
1answer
288 views
How to model a many to many from a DDD perspective in UML?
I have a two entity objects Site and Customer where there is a many to many relationship. I have read you try not to model this in DDD as it is in the data model and go for a unidirectional flow.
If ...
3
votes
2answers
450 views
What is a value object in domain-driven design?
I have an entity and I've realised that there is a group of properties that work together. So, I moved them to a value object (together with their behavior) and now I have a reference from my entity ...
8
votes
3answers
926 views
Are Domain Objects in Domain Driven Design only supposed to be write-only?
I've been reading about Domain Driven Design for almost two years and have been cautiously been introducing some concepts in to my daily work or at least making plans for how things I do regularly ...
0
votes
4answers
239 views
To which layer does this code belong?
When I say "Revisional Data Model", I mean a data model where information is never lost: Deletes never destroy any rows, and updates always cause an insert somewhere else to preserve a row's previous ...
3
votes
3answers
2k views
DDD with ORM where should the business logic go?
I have used an MDA (model driven architecture) tool in the past where we modeled via UML and this generated the business entities (our domain model) and the ORM (mapping etc) amongst other things.
A ...
3
votes
2answers
688 views
Should I use an aggregate root when designing my repository?
I have an entity that is called Master which is composed of a number of Slave entities.
There can only be one Master in my database and I want to query repositories to get the Slave for a given id.
...
11
votes
4answers
2k views
What is Domain Driven Development in practical terms?
I heard about Domain Driven Development from a developer in the area. He talked it up like it was just about the silver bullet to changing requirements.
I read the wiki. Still not too clear. What ...
10
votes
4answers
408 views
Avoiding bloated Domain Objects
We're trying to move data from our bloated Service layer into our Domain layer using a DDD approach. We currently have a lot of business logic in our services, which is spread out all over the place ...
12
votes
2answers
1k views
Where we should put validation for domain model
I still looking best practice for domain model validation. Is that good to put the validation in constructor of domain model ? my domain model validation example as follows:
public class Order
{
...
11
votes
2answers
451 views
Is DDD-Lite a pattern language for dependency injection?
I stumbled upon Greg Young's talk 7 Reasons why DDD Projects Fail where he mentions something he calls DDD-Lite at 7:20.
Summarizing, he basically says some use DDD as a pattern languages (entities, ...
6
votes
1answer
306 views
Do ORM POCOs replace domain entities?
This is somewhat similar to this question but more broad.
In general, with ORMs like EF 4.1 supporting POCOs, does it now make sense to have your domain entities be the objects that are persisted to ...
4
votes
4answers
989 views
Is it bad practice for services to share a database in SOA?
I have recently been reading Hohpe and Woolf's Enterprise Integration Patterns, some of Thomas Erl's books on SOA and watching various videos and podcasts by Udi Dahan et al. on CQRS and Event Driven ...
5
votes
2answers
264 views
How to define the seams between the domain layer and a database full of stored procedures?
We have a legacy database full of stored procedures.
These stored procedures are somewhat CRUD-categorized but upon inspection of some procedures, they are not "simple" as they might update, delete, ...
10
votes
2answers
2k views
DDD - Does an aggregate root's repository handle saving aggregates?
I am using a DDD-like approach for a greenfield module of an existing application; it's not 100% DDD due to architecture but I'm trying to use some DDD concepts. I have a bounded context (I think ...
3
votes
1answer
164 views
How a .NET dev team should be designing and delivering greenfield projects? [closed]
Some of the hottest topics in the software world atm are:
Domain-Driven Design
SOLID principles
Agile methodologies
ORM
Now assuming that you are not currently using all of these in your team, ...
5
votes
2answers
1k views
Command handlers and DDD
I have an ASP.NET MVC application, that uses a query service to get data and a command service to send commands. My question is about the command part.
If a request comes in, the command service uses ...
5
votes
3answers
831 views
Inject dependency as method parameter instead of constructor parameter
I'm using an ORM which doesn't allow me to inject dependencies in the constructor. Let's say I'm using DDD for the business logic, and the MVC pattern for the UI.
Now one of my domain objects needs ...
2
votes
1answer
196 views
Should the domain model include all the domain entities in my project?
I have currently reading Grails and I love it. In order to get hands on experience with Grails I decided to create a web application for some Management System. Ya as you can guess there are plenty of ...
11
votes
1answer
1k views
Domain-Driven-Design - external dependencies in the Entity problem
I'd like to start Domain-Driven-Design, but there are several problems I'd like to solve before starting :)
Let's imagine I have a Groups and Users and when user wants to join a group, I'm calling ...
2
votes
4answers
228 views
Data access for composable applications
I'm wondering if anyone can share their thoughts, experience and guidance on how to approach the data access layer for a composable application?
By composable application, I mean an application with ...
5
votes
1answer
134 views
Tools to support learning a new business domain
Suppose you just accepted a job, writing code in an industry sector that you've never worked in before. To be effective, you want to immerse yourself in the business domain - to understand the ...
6
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1answer
830 views
Architecting a modular service application
I'm looking at architecting a new solution that is very modular by nature and would like to create a structure that supports that design to allow for easy future expansion, clear separation of ...
