domain-model

I have a persistence ignorant domain model that uses abstract repositories to load domain objects. The concrete implementation of my repositories (the data access layer (DAL)) uses entity framework to fetch data from a sql server database. The database has length constraints on a lot of its varchar columns. Now imagine that I have the following domain class: public class Case { public Case(int id, string text) { this.Id = id; this.Text = text; } public int Id { get; private set; } public string Text { get; set; } } And an abstract repository defined as follows: public abstract class

I'm looking for a simple example to illustrate the benefits of using a rich domain model. Ideally, I'd like a before and after code listing (which should be as short as possible). The before code listing should show the problem being solved using an anemic domain model, and a lot of fairly procedural service-layer code, and the after code listing should show the same problem being solved using a rich, object-oriented domain model. Ideally the code listing should be in Java or Groovy, but anything fairly similar (e.g. C#) would do. I'll give you a simple example of real production code: Person

I represented my data model as case classes typing values that may be null as Option. case class Document(id: Long, title: String, subtitle: Option[String]) Now I try to instantiate the case class: Document(123, "The Title", "Subtitle") // Doesn't work But NOPE! This doesn't work, I have to wrap the optional value in a Some. Document(123, "The Title", Some("Subtitle")) // Works Scala is very clever about types in general, but why is it not self-evident that a hard coded literal, or (any string for that matter) is a different than null/None? I was able to fix this and make Scala "more clever"

What I'm trying to do is create a domain model with a Plain Old PHP Object. The I'm creating a library which will do all the infrastructure stuff. So one of my models looks like this class Project { public $id; public $name; public $typeId; private $type; public function getType() { return $this->type; } public function setType(Type $type) { $this->typeId = $type->id; $this->type = $type; } } Now if create a new Project and call setType with a valid Type object and save the project instance using the ORM both the project and type is saved. But then I load the Project and use getType method I

In Domain Driven Design, one of the defining characteristic of an Entity is that it has an identity. Problem: I am not able to provide a unique identity to Entities on instance creation. This identity is only provided by the repository once the entity is persisted (this value is provided from the underlying database). I cannot begin to use Guid values at this point. The existing data is stored with int primary key values and I cannot generate a unique int on instantiation. My solution: Each Entity has an identity value The identity is only set to a real identity once persisted (provided by the