Elements Of Programming Languages (C. Data Level Structure)

 Data level structure?

three levels of data abstraction
are:
1. Physical level : how the data is
stored physically and where it is
stored in
database.
2. Logical level : what information
or data is stored in the database
(like what is the
datatype or what is format of
data.
3.View level : end users work on
view level. if any amendment is
made it can be
saved by other name.
for the database to be usable it
must retrieve data efficently.this
efficency led designer to use
complex data structure in the
database

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