Question - What are the three levels of data abstraction?
Answer -
Following are three levels of data abstraction:
Physical level: It is the lowest level of abstraction. It describes how data are stored.
Logical level: It is the next higher level of abstraction. It describes what data are stored in the database and what the relationship among those data is.
View level: It is the highest level of data abstraction. It describes only part of the entire database.
For example- User interacts with the system using the GUI and fill the required details, but the user doesn't have any idea how the data is being used. So, the abstraction level is entirely high in VIEW LEVEL.
Then, the next level is for PROGRAMMERS as in this level the fields and records are visible and the programmers have the knowledge of this layer. So, the level of abstraction here is a little low in VIEW LEVEL.
And lastly, physical level in which storage blocks are described.