1
vote
2answers
94 views

Where should the “not empty field” validation code be written on a 3-layer application?

When working with the 3-layer model, where should the validation code be placed? for: not empty fields, unchecked options, null values, wrong-written dates, etc. To keep total isolation between a ...
0
votes
2answers
98 views

Can a layer consist of multiple projects / dlls?

I am working on the architecture for a new web application and I am pretty much a complete newbie when it comes to architecture. Working my way through .NET Application Architecture Guide, 2nd Edition ...
2
votes
1answer
126 views

Where do utility libraries fit in a layered architecture?

Consider this mock-up of a software stack designed with layered architecture in mind : Every application layer is decoupled through API calls, but a memory handling library is used throughout. All ...
1
vote
1answer
81 views

Data Access Layer for application

I am working on a retail application where currently I'm using raw SQL like insert into some_table values (Textbox1.Text, Textbox2.Text, ...) and update some_table set some_column = value for ...
1
vote
1answer
131 views

Where does non-MVVM code belong in an MVVM app?

By non-MVVM code, I mean things like highly generalized components, like one with common extension methods for CLR types, and other 'homeless' helper classes etc? I have a Core project that most ...
0
votes
1answer
110 views

Layer style applied, but intuition is different

Currently, I'm developing an architecture for a system of the following kind: There are a couple of existing applications (front end) with which one can define UML profiles capturing some specific ...
0
votes
0answers
54 views

Layer Encapsulation without Model Overload?

I'm starting a new project, so it's time to re-evaluate how I do things. In the recent past I have created a 3 layer/tier project (UI, Domain, Data) with each tier with it's own separate model. The ...
1
vote
3answers
405 views

Which layer does async code belong?

I am developing an application that consumes data from an external service. The application is being implemented following a typical layered architecture with UI, Presentation, Domain and Data ...
62
votes
13answers
5k views

Why is it a good idea for “lower” application layers not to be aware of “higher” ones?

In a typical (well-designed) MVC web app, the database is not aware of the model code, the model code is not aware of the controller code, and the controller code is not aware of the view code. (I ...
3
votes
1answer
269 views

Why doesn't layered architecture translate easily to tiered architecture?

Basically, I'm trying to understand why layered and tiered are that different, and why they don't translate easily to each other. I understand that layered could be 3 separate class files for UI, BL ...
2
votes
2answers
1k views

Presentation VS Application layer in DDD

I have trouble drawing a clear line between Presentation and Application layer in Domain Driven Design. Where should Controllers, Views, Layouts, Javascript and CSS files go? Is it in the ...
1
vote
1answer
157 views

When do domain concepts become application constructs?

I recently posted a question regarding recovering a DDD architecture that became an anemic domain model into a multitier architecture and this question is a follow-on of sorts. My question is when ...
0
votes
6answers
2k views

When to use the 3 layers model?

I was recently exposed to the three layer model (DAL,BL,UI). Someone told me I should ALWAYS work with this model. I have a medium project that I'm starting and I have doubts whether I should build ...
2
votes
3answers
622 views

Recommended content for layers

As an expansion from my previous question about using separate projects for seperate layers - Good practice on Visual Studio Solutions I now wish to know if I am putting the right functionality in ...
1
vote
1answer
1k views

What are “User Process Components”?

This article about application architecture design mentions "User Process Components" as part of the presentation layer. User process components. Your user process components help synchronize and ...