A domain model is composed of the objects, behavior, relationships, and attributes that make up the industry that is the focus of development.

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Domain model design

In your own opinion, which is a better design. A User object which contains an attribute Employee, and that Employee is being inherited by more specific job title. or is it better for the Employee to ...
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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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Design to link two model classes with different multiplicity

It is usually well known how to deal with model classes that have a 1:N relationship: classical examples are order->items or client->orders. Every layer of the software has its appropriate and ...
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How to correctly model aggregation with respect to persistence?

When modeling bigger domain entities you will probably have some kind of relation between these entities. These relations will usually result in entities referencing different entities. If i am not ...
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617 views

Web application / Domain model integration using JSON capable DTOs

I'm a bit confused about architectural choices for the web-applications/java/python world. For c/c++ world the available (open source) choices to implement web applications is pretty limited to zero, ...
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How do you represent an object when you need to know which subtype you're working with?

I have some data that I need to represent in a form. As an example, it might look like this (in psuedo-json): [ { "value1" : "int" "value2" : "{1, 2, 3, 4, 5}" "value3" : "...
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Should domain models instantiate other domain models?

I'm reading Domain-Driven Design at the moment and I'm trying to understand what should go in services and what should go in domain models. Say there is an application where you can reserve seats for ...
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130 views

Ubiquitous language and resource based REST API?

I have posted a question regarding Ubiquitous language and maturity level in REST API. Ubiquitous language and maturity level in REST API? After some extensive coding I realized that further ...
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Could REST api be considered as a presentation layer in DDD?

I read a lot of questions about this concern, and some of them are Presentation VS Application layer in DDD Application layer vs domain layer? So my question is if the top layer is REST API and ...
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255 views

Domain/Model objects attributes good practices

Simple question: Should model/domain objects only include attributes that are meant to be persisted in a database or serialized to any other specific format? My understanding of a domain/model object ...
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Domain object using DAO within a transaction

Is it considered good practice to start a transaction in the "service/application" layer, and then have objects in the domain model make DAO calls which participate in that transaction?
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189 views

Ubiquitous language and maturity level in REST API?

According to Richardson Maturity Model there are several levels of maturity in REST approach. http://martinfowler.com/articles/richardsonMaturityModel.html Since DDD uses ubiquitous language, I am ...
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Automated data processing in BPMN/BPEL?

In order to run complex simulations, I need to do preprocessing of data from various data sources. This is done by a bunch of Postgresql scripts. However, having only these is unsatisfactory, because ...
2
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Design patterns to limit cross module logic

I have a web application which has a shopping cart with cart items. The cart items are added to the user session, so must be serializable. I have a checkout class which takes the cart items and saves ...
4
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MVP / MVC role of the Model (not anemic one) clashes with presenter / controller role (responsibilities in the right place, Model OR Presenter)?

Problem? I have been looking at MVP implementation and process to design a good domain model (not anemic). It says that the domain model should have its own behavior and not being a simple data model ...
2
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4answers
154 views

Design ideas - validation based on conditions outside of the domain

I am facing a very interesting problem here, and I'd like to see some design ideas from domain driven design perspective. To make it easier to express what I need I have following hypothetical ...
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249 views

Choosing an ubiquitous language across different bounded contexts

If my domain has several Bounded Contexts, but only ONE team will work on all contexts, should I develop an Ubiquitous language for each context? or should I have only one and force to into all ...
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4answers
210 views

Domain Driven Design and Cross Domain interaction

I am a relative DDD newbie, but I am reading anything and everything I can get my hands on to boil out and distill my knowledge. I came across this DDD question, and one of the answers has me ...
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1answer
197 views

DB modeling for staffing demand and supply

TL;DR - I'm looking for guidance with my database design. I am concerned that my existing design is inefficient and won't be able to handle large numbers of employees. This is going to be long, so ...
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How to prevent parallel calls to model?

While there is some command running which calls methods on some model, how to prevent concurrent calls for critical places in that model? If multiple requests comes in then they should maintain their ...
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Justification for bidirectional relationship

I typically try and avoid bidirectional relationships at all costs. Recently I've been trying to follow a more domain centric design philosophy and I'm looking for advice in the best way to solve a ...
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Alternative to Anemic domain objects (Simple example provided)

I want to model (TV)Events and Reminders and I’m wondering what’s ‘the best’ way to model this. The requirements are roughly When an Event has no Reminder, a Reminder can be created When an Event ...
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153 views

When a class represents a property that might be invalid, how should the validation be done?

I have a Product class which has among others an attribute Ean13 that encapsulates an EAN13 code. Here is a prototype of the Product class: @Entity @Table(name = "tb_produtos") public class Product ...
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Lookup Tables: Are they a leak in the domain model?

You are building a system that keeps track of Companies. Those companies have Contacts. Those contacts are often specialists that only answer certain types of questions, such as Billing/Payment, Sales,...
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How to handle Data Fetching for Circular Object References in OOP Domain Models

I'm trying to put together some basic models in OOP (C#), and apparently I've got the wrong idea. If I have a Workman's Comp case, it is applied to a Patient. It also has one or more PatientVisits ...
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Should API DTOs be shaped to client(s) or be universal?

I have a project with an internal desktop client app and a server-side client API service talking to a relational database. I seem to have two choices: 1) shape DTOs to client views, e.g. ...
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TDD: How to test domain model

When practicing TDD, how do you test a domain model? If you don't test, how do you account for code coverage? We want to have 100% coverage (or as much as possible), but despite hours of training ...
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What to do when hydrating whole domain model is unnecessary for concrete operation?

If some model can only exist if set of values are passed to it and validation on them are performed, then how to load such a model if only one of those values is needed for some action? It seems a ...
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ID properties on Domain objects in DDD

In my domain I have an Account object. e.g. class Account { public string Number; public string SortCode; } Within the context of DDD, should this account object have an ID property? The ...
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1answer
374 views

Domain Model vs Presentation Model vs General Function

I have been building an app for my company i join for the past > 1 year, we're using Java Spring Hibernate Javascript jQuery Kendo UI And for the structure i can say something like this from ...
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1answer
512 views

How to present domain model exceptions thrown through validation

In domain model of my web application I've an entity Foo which can be created only by a pojo FooBean: Foo.newInstance(FooBean fooBean) (Might have been better a Builder-pattern.) In the factory ...
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3answers
189 views

DDD design question

I have a question on modelling an Entity\Aggregate root in DDD. I am refactoring a project that uses Entity Framework and business logic as services, the services contain lot of logic which I believe ...
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Should well-known business ID of an entity be represented with a dedicated type in DDD/OOP?

In practical terms it means using an custom (immutable) class over a string or some other primitive type. Examples: Publishing: International Standard Book Number. Finance: International Securities ...
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Should domain model be intelligent or there must be services, which operate it?

I'm building a web-app for a licensing service. My domain models are Licenses, and they can be of two types at the moment: server and client license. They are almost same, except server license has ...
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How can I create a model to efficiently answer the question of - where to place my db-interaction code I am about to write?

I am seeking the right model for storing and retrieving data, when working with any specific class, while keeping in mind the bigger picture. Details: I have some SQL code in (one) of my classes and ...
4
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1answer
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Strategy to define domain data used in Integration Tests

In my job we work in a data driven web application and performance is a important business feature. So, queries in the model tier are frequently large and contain much of the business logic. As a ...
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2answers
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Authenticate in the Services? Or in an Endpoint that exposes the Services?

When I'm in charge, I typically model services separate from endpoints. For example: Company.Project.Domain.dll has all of the logic required to complete the services for that domain. In order to ...
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Should a domain object wrap/contain a DTO interface?

Using .NET - I have an interface IPerson. This interface is implemented by classes in multiple, separate repositories, e.g. EF6 (EfPerson), custom SQL (SqlPerson), or even custom assembly connecting ...
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269 views

Domain object model: query by id vs object

Let assume I have two simple model classes: Product and Brand It is obvious I have a query method in Product class like this Product product = Product.findById(123); What if, I want to query ...
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DDD using an ORM and a Active Directory Server for Persistence

With Domain Driven Design one would model out the domain. One would then use an ORM of some sort to take care of the persistence. Say you have a Product entity which has a Name, SKU and an Owner. This ...
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Should I use inheritance to differentiate objects even if they have the same fields?

Consider this simple class that models a real world mobile device: /// <summary> /// Model that represents a device. /// </summary> public class Device { public DateTime ...
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How do I model this relationship so that it is valid by construction?

Imagine a device class that represents a physical real world mobile device, with fields like Enabled, Platform, Model IMEI, etc. Then, an operation class, which is something that needs to be done to a ...
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340 views

How to use DDD to solve a common address situation?

This is a simple example to show a situation that I find hard to solve with DDD. Consider this: - A property (e.g. a house) has an Address. - An address can be complete or partial (country only; ...
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252 views

Handling Business Logic/Validation Race Conditions

I'm working on a Training Enrollment web application with the following (simplified) features: Maintenance (Add, Edit, Deactivation) of Trainings Student sign-up Student enrollment to Active ...
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Rails: get data about a model collection, with new model or method?

I have a model Product with attributes sales and views. I need to get sales/views count of all the products. Is more correct to implement this as a method and have a call like Product.all.sales or ...
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225 views

Implementing an anti-corruption layer with domain logic

I'm building an application that compiles a single PDF document from multiple source PDF documents as follows: it takes the first page of each source document, stamps certain information on top of ...
3
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2answers
99 views

Domain Modeling - Offerings vs. Usages

I have a question about an issue I always seem to run into when building a domain model. The issue comes up whenever a domain object is used in what I am calling an "offering" scenario and in a "usage"...
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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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Class Table Inheritance: do child tables need a primary key?

I'm using the Class Table Inheritance architecture with my application and have read Fowler. When mapping my database tables to classes in code, I've realized I have no need for an "ID" property on ...
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Clean architecture: should users go in the use case layer or the domain layer?

I recently read this article about Clean Architecture, as I'm trying to get out of some usual OO habits (interface design everywhere, but what does it do???), and program something that describes what ...