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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Enterprise application object oriented modeling for user and role

Generally in the Enterprise Applications like ERP or ERM, CRM, BP etc. we see two things a lot, one of them is Role and the other one is User. What happens is that in the real world we have some ...
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What are subdomains, really?

In studying domain-driven design (DDD), I've come across the concept of subdomain, but I think I don't get it yet. My first understanding of this was that a subdomain is a subset of the domain of the ...
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261 views

DDD Validation best practice: entity containing data doesn't have the context to validate before data is set. Where should set function be?

I am pretty new to DDD, so bear with me. I have a Chat room and people in the Chat room. The people in the chat room need to propose a date they would like a webinar to be on. we have a bussiness ...
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1answer
305 views

Should I be using separate 'domain' layer?

I have been reading a lot about domain layer and DDD. However I am still confused about it. To me they seem to be a fancy name for business classes however more modelled towards your application ...
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237 views

Repository Pattern and custom queries/REST API. Is it the right approach?

I'm in the early stages of working on an application that is using the Repository Pattern to provide a data access abstraction. This application will have some form of a simple REST API but I'm not ...
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218 views

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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1answer
43 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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46 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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2answers
108 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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2answers
62 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
95 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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216 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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110 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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153 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 ...
0
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1answer
98 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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2answers
288 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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3answers
123 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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1answer
156 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
85 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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630 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
71 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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1answer
82 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
95 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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1answer
263 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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3answers
773 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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83 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
110 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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1answer
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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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1answer
407 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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2answers
101 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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1answer
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“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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1answer
275 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
60 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
211 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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1answer
139 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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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
303 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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1answer
98 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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2answers
317 views

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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339 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 ...
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1answer
62 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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1answer
118 views

What should the payload of a “domain event” generated through “change data capture” include?

Using domain driven design and event sourcing ... Given I have a table of 3 columns: (A, B, C) with an existing row of data: (1, 2, 3), when I update the row to contain values (1000, 2, 3) and I run ...
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4answers
477 views

Domain Model, validation, and pushing errors to the model

Looking into DDD and something I noticed is that business logic should be in the model, otherwise you just have property bags. That said how do you handle pieces of validation that require a trip to ...
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3answers
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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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0answers
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Is there a pattern for deserialization involving repository access? Or what is wrong with my design?

Let us have case class Money(amount: BigDecimal, currency: Currency) case class Currency(code: String, alpha3: String) Money is a value object and Currency is an entity. When transforming Money to ...
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2answers
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DDD - If an object is saved as a whole to the database, is it per definition an entity, or is it still possible that it is a value object?

I'm learning about Domain Driven Design and struggling with the question if a particular object should be handled as entity or value object. All possible surname prefixes are kept in a database ...
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1answer
352 views

Separation of concerns between repository and service in DDD with complex entities

This probably seems as an example of opinion-based question, but I'm actually looking for rationale on how to decide correctly, I believe there is a correct solution that can be backed by solid ...
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3answers
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Is there any reason to override Equals for an Entity?

An entity has identity, which implies there should only be one object (e.g. a particular customer) in memory. As such, reference equality (which is what the base version of object.equals checks for) ...
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Is this a good Visual Studio solution structure for a domain driven design RESTful web service?

I am building a .NET 4.5 C# Web API RESTful solution and I would like someone to tell me if my project solution is correct and/or wise(-enough?) for a solution designed using Domain Driven Design, ...
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Domain model associations that do not required the behaviour of the associated object. How to model?

I've been struggling with this question for a while. I'm specifically thinking within the object orientated domain model. Let's say I have two entities. A supplier and a customer. There is a ...