n-tier application desing

[paulthepaddy]

Hi Guys, i am buildiong an appliation that i am tying to understand and think would it be worth while turning into an n-tier application, would like some thoughts from you guys on what i think is a good idea :S

been reading up on 3 tier appliocation design, but i don't think that would really apply to me, we are a small family company so their isn't going to be massive amounts of user using this application, so i can't see the 'Business Rules' tier being really useful to me. from my understanding the business rules is a layer that would validate and handle data before it goes into the DAL, but alot of my formatting gets done by my client and the class's it would use eg

Private _Reg As String
    Private _DateDone As Date

    Public Property Reg As String ' Car Reg
        Get
            Return _Reg
        End Get
        Set(value As String)
            _Reg = StrConv(value, VbStrConv.Uppercase)
        End Set
    End Property

so could some advise me if it is a bad idea if i dont use a business rules layer?

 

[IanRyder]

Hi,

A few comments from me are:-

The typical 3 tier application consists of, as you would expect, 3 layers of logic:-

1) The Presentation Layer (i.e forms, controls etc)
2) The Business Rules Layer (i.e what are you currently wanting to do / show with the information you have)
3) The Data Access Layer (i.e communication between your project and your Data Source)

In principal, the reason for having 3 different layers of logic is so that if any one piece of logic needs to be modified at some future date then you know exactly where to look to start making the modifications that you need.

Now the easiest of the 3 layers to envisage are the Presentation Layer, since this is where you design your application and the Data Access Layer which can easily be demonstrated by using the Data Source Wizard to add a Strongly Typed DataSet to your application. This then adds an "XSD" file to your project which can then be used to communicate with your Database in its own Data Access Layer.

The one layer that sort of blurs the boundary of a "specific layer" is the Business Rules Layer since this is effectively a combination of the code behind the Presentation Layer (i.e, the code in the Form) and any other specific Class's that you may design to interact with the Presentation Rules Layer and/or the Data Access Layer.

Hope that helps.

Cheers,

Ian

 

[paulthepaddy]

Hi Ian,
Thanks for getting back to me, and sorry for the very late reply, thanks to JMCs reply i no longer need to use an n-tier application design, i am going to be using the Sync framework, which has made me use WCF Library and a Website to host it, i have already bought a we cheap server for the hosting of the things im going to need and just going to make the client do most of the progressing as the server isn't a massively powerful one.

but thanks for your reply, i do apopreicate the times it take to go through the forum and reply to different threads and i appreciate the knowledge you guys provide