Today I am going to show you how to write Data Access Layer (DAL) and Business Access Layer (BAL) using the CsharpGears Framework.
One of the most accepted approaches of the today's application architecture is the 3-tier architecture, or it's general version n-tier architecture. The idea is to separate the logic of the application in separate layers, each of which will be able to communicate in a standardized way with another layer. Most often, the tier that is responsible for displaying the data is called the presentation layer, which is capable of invoking the layer that holds all the business logic - namely the business layer. The business layer, however can either be invoked by the presentation layer and return the results of the execution to it. In certain situations, the business layer will need to access some amount of data in order to perform all the calculations. In that case, the business layer invokes the third layer - data layer. The data layer is responsible for retrieving the sets of data from some source - be it a database or xml file or web service - it can be literally anything.