Database systems are made up of complex data structures, to each user interaction with the system, the developers often hidden the internal irrelevant details from the user. The process of hiding irrelevant details from the user is known as data abstraction. Data abstraction is the reduction of a certain portion of data for a simple presentation of content. Abstraction, in general, the process of removing features from something to reduce the set of necessary features. Data abstraction is usually the first step in database design. Creating a system without creating a complete database first simplified structure is much more complicated. Data abstraction allows the developer to start with the necessary elements – data abstractions – and add the declining data detail to create the final system which done by three levels of data abstraction.
Levels of Data Abstraction:
Three main levels of data abstraction are as follows:
- Physical level: the physical level is the lowest level of data abstraction. It describes how data are stored in the database system. We can get the complex data structure at his stage.
- Logical level: It is the middle level of the three-level data application. It describes how data are stored in the system.
- View level: the highest level of data abstraction. This level describes the user interaction with the system.
For example, suppose we are storing customer’s information on the customer’s table. At the physical level, these records may be described as blocks as storage in memory. These details are usually hidden from the programmers. At a logical level, these records can be described as fields and attributes, along with their data type and their relationships with each other. Programmers generally work at this level because they are aware of such an about database system.
At the view level, the user just interacts with the system with the help of GUI (Graphical User Interface) and enter details at the screen, they are not aware of what data is stored, how data a stored. These details are hidden from them.
Studying at the University of Rajshahi.