The three layers that are involved in the data accesses and modeling are: 1.Physical layer: This is the layer where the actual raw data is stored in the form tables. These are very descriptive data and are meant for use by the business layer of logic. 2.Business layer: The more higher level of interface to the data sources, that makes the logical interpretation much feasible and easy. 3.Presentation layer: This is what is given out to the user. All the processed and categorized data give the clear picture of the real world entities using the raw/combination of multiple data from the physical sources through the business layer logics.