This is a very significant subject to reflect on when developing an application. Many elements required to be considered when choosing on the architecture of the application, such as performance, scalability and future development issues. When you are selecting on which architecture to use, first select on which of the mentioned elements you think is most important as some selections will make some sort of impact on others. For example, some choices that increase performance will bang on the scalability or future development of your design, etc.
What is n-Tier architecture?
N-Tier architecture submits to the architecture of an application that has at least three logical layers. Each layer interrelates with only the layer straightforwardly below, and has precise function that it is accountable for.
Why use n-Tier architecture?
Because each layer can be located on actually different servers with only minor code alters, hence they scale out and knob more server load. Also, what each layer does internally is completely concealed to other layers and this makes it possible to change or update one layer without recompiling or adjusting other layers. This is a very prevailing feature of n-Tier architecture, as additional features or modify to a layer can be done without redeploying the whole application. For example, by separating data access code from the business logic code, when the database servers modify then it requires to alter the data access code. Because business logic code stays the same, the business logic code does not require to be altered.
An n-Tier application frequently has three tiers, and they are called the presentation tier, the business tier and the data tier. Let's have a look at what each tier is accountable for.
Presentation Layer
Presentation Layer is the layer answerable for showing user interface and driving that interface using business tier classes and objects. In ASP.NET it includes ASPX pages, user controls, server controls and occasionally security related classes and objects.
Business Tier
Business Tier is the layer accountable for accessing the data tier to reclaim, adapt and delete data to and from the data tier and send the results to the presentation tier. This layer is also dependable for dispensation the data recovered and sent to the presentation layer.
BLL and DAL
Frequently this layer is separated into two sub layers: the Business Logic Layer (BLL), and the Data Access Layers (DAL). Business Logic Layers are above Data Access Layers, significance BLL utilizes DAL classes and objects. DAL is accountable for accessing data and forwarding it to BLL.
In ASP.NET there are four security models that can be used in web applications.
1. Form security
This is perhaps the most frequently used security model in ASP.NET websites. It's very expedient to use and is faultless for most applications. If you require role based protection then characteristically this is the way to go.
2. Passport
If you want your visitors to be able to use their passport account at your website, you can execute the passport security model. To use this security model you require to be able to access the Internet, so it's not really appropriate for intranet applications.
3. Custom Security
If you require a more complex security system, then you will want to execute your own security system. This is characteristically done by creating your own principal and identity classes.
4. Windows Security
This is ideal for intranet websites. It converses to an Active Directory for user authentication information where all of the groups, permissions and users are supervised.
In this post we've looked at a diversity of issues connecting to the .NET web application architecture, such as tiers, security, and class design. Hopefully the tips and tricks drawn as a .NET developer have assisted you in good health for the design of your next project or application.