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