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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Does snapshot change tracking break DDD principles?

I'm building a website with MVC 5 and Entity Framework 6, implementing the Unit of Work & Repository patterns, and - for flexibility and performance - would like to utilize Entity Framework's ...
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3k 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: ...
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55 views

Is Domain Driven Design died? [closed]

Is domain driven desing are still valid or died? Because architecture of software is changing day by day. I read books about DDD that writed 3-4 years before.
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13 views

How to model parallel processes (in a Bounded Context) with the same data store?

The situation. Let's say a background process puts stuff into data containers. It runs all the time, observes system events, and populates the data accordingly. The user may launch a control panel ...
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5answers
3k 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 ...
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23 views

Domain Analysis vs System Analysis

I am trying to determine the differences between systems analysis and domain analysis. It seems that any systems analysis occurs within a domain--so are there techniques, concepts, tools, etc. that a ...
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23k 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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1answer
258 views

From a DDD perspective is a report generating service a domain service or an infrastructure service?

Let assume we have the following service whose responsibility is to generate Excel reports: class ExcelReportService{ public String generateReport(String fileFormatFilePath, ResultSet data){ ...
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201 views

Is DDD any good nowadays? [closed]

This is not a rant about DDD but rather some experiences and observations I've made through the past 2 years since I first learned about it. With this post, I'd like to hear what other programmers ...
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2answers
96 views

Should ids be mapped to the implementation type

This is a question of model design, and hopefully some architecture nerds have strong opinions on this. I've been developing one that I will post in an answer. Typically, in every codebase I've ever ...
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1answer
67 views

How to model Aggregate Roots for this music event system?

Let's say I am modeling a music event system. I have: music events listing events (the items in a lineup) - a listing event has acts (the artists playing in an item in the lineup - these can be ...
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1answer
29 views

Is it normal for service methods to correlate to your views?

I've been working on learning how to implement domain services and view models in my project and have noticed a suspicious trend: When obtaining data for views from my controllers, if my domain ...
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1answer
56 views

Integration between services in a SOA

Assume we have a Bounded Context for Inventory (InventoryBC) and another one for Shipments (ShipmentsBC). These 2 BCs need to communicate together. They are hosted on 2 different services on different ...
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2answers
49 views

How to add new child entity to a repository in DDD?

I'm new to Domain-Driven Design and I'm using it in an application I am developing. I'm getting stuck on how to put new entities into a repository. My repository is just a big collection of entities ...
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1answer
43 views

Event Storming: How to phrase a command initiated by an actor, and where to put it software-wise [closed]

In Event Storming, there are "Commands" (blue sticky notes) which are, in most cases, triggered by an Actor. How should these commands be named, prosa-wise, especially in relation to the actor? ...
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1answer
28 views

Models, types, different views and meta data

We have a software which purpose is to be used to help users build their own applications. It has to be very loose coupled with the infrastructure: for example, I can imagine users running it on MySQL ...
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1answer
184 views

PHP - Repository matrix pattern?

I'm trying really hard to refactor some of my legacy code in the project using best practices and design patterns + DDD so I'd love some feedback on an issue I'm currently having. Let's assume that I ...
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3answers
113 views

where should put showSchedule method in school system

In my school management system I have this partial class diagram: 1- In one use case student want to see his schedule of classes in week. this is what i suppose to do: get student object from ...
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5answers
288 views

Is DDD not appropriate for my website or should I introduce a Query Layer?

I have inherited an ASP.NET website application and the previous developer has used what I believe are some DDD concepts. I am new to DDD and I have to admit I am struggling with the practical side of ...
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1answer
108 views

What is eventual consistency?

I've heard people talking about "eventual consistency" (for example in this question and this answer). What is "eventual consistency"? How does it compare to "transactional consistency"? When does it ...
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1answer
56 views

Starting a big application with unit testing [closed]

I am learning test driven develeopment and read some books about TDD. I learned rules of unit testing. How can I write unit test, how can I select test method names, Act, Assert, Action and like this. ...
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0answers
67 views

When is it appropriate to map a DTO back to its Entity counterpart

From what I've read and implemented, DTO is the object that hold a subset of value from a Data model, in most cases these are immutable objects. What about the case where I need to pass either new ...
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1answer
94 views

How do I Create Automated UI test code for application developed using Domain-Driven-Design with very little concrete UI requirements?

We are developing an application using Domain-Driven-Design(DDD). We have to come up with Automated UI Test code. The customer has used 3rd-party GUI Administration template ...
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1answer
57 views

Domain Driven Design and Data Conflicts

I realise it is probably overkill for what is a occasionally connected client app, but the construction of aggregates roots is bugging when thinking about it from a client perspective. For the ...
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2answers
263 views

Best practices for serialization of DDD aggregates

According to DDD domain logic should not be polluted with technical concerns like serialization, object-relational mapping, etc. So how do you serialize or map the aggregates' state without publicly ...
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1answer
61 views

Non-anemic model and SRP

I'm implementing a feature in legacy system right now. Instead of putting all my logic in some dummy application services and having anemic models, I thought I will try to do some OOP this time. I'm ...
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128 views

“Implementing DDD” by Vernon: value object or not?

On page 382 of this book there is a passage talking about using value objects in aggregates, under the (entity) root. There is an example of Product that, besides other values, contains a ...
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Identifying Domain Services & Application Services when doing DDD

-I'm trying to figure out how to identify Application Services in my application. I think I can identify a Domain service by 2 things: It acts as a facade to the repository. It holds business logic ...
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71 views

New DDD, context-oriented, functional… approach in building business layer [closed]

We are building some business modules that must be intuitive for developers to use, so the code itself explains and forces developers to use it in certain way. This applies both for enhancing the ...
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69 views

What are the boundaries of Domain Events?

As I get it, domain events imply loose coupling and separation of responsibilities. That's fine. But if domain events are allowed to cross aggregate's boundaries then it is a question how to guarantee ...
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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 ...
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399 views

DDD, modularizing the application and domain layers without breaking the DIP

Quoting DDD theory: The application layer is thin in terms of domain logic - it merely coordinates the domain layer objects to perform the actual work. When it comes to modularization, and ...
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79 views

What and how much domain code should be put in an F# module

According to recommendations given here, F# modules should correspond to DDD bounded contexts, i.e. subdivisions of a business domain. The bounded context I'm working on right now has 2 aggregates ...
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55 views

DDD models and localization?

Let's say I have a Book that has it's title and description localized in any number of languages. Localization only matters for e.g. administrators, because users chooses their localization and they ...
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DDD and edit of Aggregate's descendants

In a DDD approach, suppose I have an Order (this is my aggregate root) and a Line (a descendant of an Order). In both objects I have private setter for properties and a builder that handle creations ...
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266 views

How does a search functionality fit in DDD with CQRS?

In Vaughn Vernon's book Implementing domain driven design and the accompanying sample application I found that he implemented a CQRS approach to the iddd_collaboration bounded context. He presents ...
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137 views

Event sourcing - performance penalty? [closed]

I am trying to convince people in my company that we should switch to event sourcing. Our software is a product that consist of many modules - like a module for wiki, blogs, documents, etc. I would ...
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87 views

Reverse relationships for smaller/better Aggregates?

Let's take an example: we have two related entities, like Question and Choice. This is a poll: it contains of single question that may have 2 or more choices. Each choice can be voted for by users, ...
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48 views

DDD: storing additional data with the model

Our domain is operated within certain context. This context is described by some additional values, like a fooId - id that does not have a meaning in domain business, but it's more a flavor for the ...
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1answer
102 views

DDD: Global unique identities vs surrogate

Let's start with an example: we have an entity: Book. It has unique identity: Isbn - a value object that wraps a String. This is an UUID. The Book entity also needs a surrogate id from the repo (sql ...
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1answer
107 views

DDD: placement of method whose behavior may be implemented with single database query

Let's say we have Book entity in our library. A requirement says: Librarian may disable 'available' flag to books published before some year. For example, librarian may 'hide' some old books from ...
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5k views

Are DDD Aggregates really a good idea in a Web Application?

I'm diving in to Domain Driven Design and some of the concepts i'm coming across make a lot of sense on the surface, but when I think about them more I have to wonder if that's really a good idea. ...
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1answer
60 views

Inter-aggregate commands/transactions in an eventual consistency manner

I am trying to model a business transaction that operates on two aggregates. Let's say we have a Bag aggregate type that contains Items (entities). I would like to have a command ...
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2answers
75 views

DDD: service/repo operations on IDs or instances?

This might be silly, but: let's say I want to delete a Book from the repo. Should I: deleteBook(bookId) - send the ID since in the most of the time, the ID is passed from the UI or ...
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2answers
146 views

DDD: How to refer/select a value object inside aggregate?

We have an aggregate of: entity: Poll (representing a question) two or more value objects Choice Adding choices is done through Poll, repository stores only the aggregate, i.e. everything is done ...
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52 views

Is it ok to have special domain factory - or something similar - directly in DAL?

In DDD application, I know that Domain Factory should be the single point of Domain object creation (input from the UI, the results of queries from persistence) - but I'm facing a problem that for ...
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3answers
237 views

In domain driven design, how do I convert a database table with a primary key into a Value Object?

Lets suppose there's a database schema defined like this: Person.mail_address_key ----- Address.address_key Person.billing_address_key ----- Address.address_key A Person has a mailing address and a ...
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75 views

DDD: Alternative view of the Model?

I have a model class, let's say it's a Book. I need it to be displayed on the screen. I want to have an escaped version of it, so I do not need to escape fields manually. What should I do? I can ...
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DDD and collections and paging of related models?

I have a rich model, where e.g. one model A depends on many related entities/value objects. Therefore we have methods in A for retrieving collections of related objects: getFoos(), getBars() and so ...
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250 views

Model relationships with DDD (or with sense)?

Here is a simplified requirement: User creates a Question with multiple Answers. Question must have at least one Answer. Clarification: think Question and Answer as in a test: there is one ...