| Â | | | | object, or a custom collection object. The Data layer |
| Architecture is an important feature and the very | | | | gets the data from the business layer and sends it to |
| first step in the development of an application. n-Tier | | | | the database or vice versa. This layer is further |
| the term is used for multiple tier or multiple layers. | | | | divided into two sub layers Business Logic Layer |
| n-Tier Architecture splits the solution process into | | | | (BLL) and Data Access Layer (DAL). DAL is |
| different projects based on the business | | | | responsible for accessing data and forwarding it to |
| requirements. The main advantage of using n-Tier is | | | | BLL. In ASP.NET it uses SqlClient or OleDb to retrieve |
| that the complexity associated with the business and | | | | the data and send it to BLL in the form of a DataSet |
| the process is reduced and it is easy to work with. | | | | or DataReader. BLL (Business Logic Layer) is |
| The elements of performance, scalability and future | | | | responsible for preparing or processing the data |
| development issues need to be considered when | | | | retrieved and sends it to the presentation layer. |
| deciding on the architecture of the application | | | | The Data layer gets the data from the business layer |
| depending on the priorities required. | | | | and sends it to the database or gets the data from |
| The n-Tier application has three tiers or layers, they | | | | the database and sends it to the business layer. In |
| are called the presentation tier, the business tier and | | | | ASP .NET it is an SQL Server or Access database. It |
| the data tier. Each layer interacts with the layer | | | | can also be Oracle, mySQL or even XML. |
| directly below, and has specific function to perform. | | | | In an ASP.NET n-tiered architecture web pages do |
| Presentation Layer is responsible for displaying user | | | | not make direct calls to the database. A given layer |
| interface to either programmer or end user. | | | | only communicates with its neighboring layers. |
| Programmer uses this layer for designing purpose and | | | | ASP.NET Web pages should reference custom |
| to get the data back and forth. In ASP.NET it | | | | objects defined in the business object layer. These |
| includes ASPX pages, user controls, server controls | | | | objects provide database information in a class |
| and sometimes security related classes and objects. | | | | structure. |
| The Business layer works as a mediator to transfer | | | | The partitioning of ASP.NET applications into |
| the data from presentation layer. In the three tier | | | | front-end, middle tier and back-end layers, the n-Tier |
| architecture the data access layer is not made to | | | | architecture supports a more uniform, building block |
| interact with the presentation layer. The architecture | | | | approach to application designs. Hardware and |
| in ASP.NET includes using SqlClient or OleDb objects | | | | software for presentation, application and database |
| to retrieve, update and delete data from SQL Server | | | | functions can be scaled separately, and included more |
| or Access databases and passing the data retrieved | | | | easily into complex e-Business environments. |
| to the presentation layer in a DataReader or DataSet | | | | |