abstractions in dbms
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Abstractions in DBMS
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Introduction:
DBMS
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Data Abstraction
First step in database design
Hiding irrelevant data
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Why Data Abstraction?
Process of simplification in both virtual and real world
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We Have Three Types
Physical Level
Logical LevelView Level
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1. Physical Level
Lowest level of data abstraction
Describes how the data is stored
Records are stored in the blocks of memory
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2. Logical LevelFurther higher level Describes how the data is
stored in a Database
May involve complex structures
No need to be aware of complexity
Used by database administrators
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3. View Level
Highest level of data abstraction
To simplify the interaction with the
databaseUser is not aware how
the data is stored in the database
System may provide many views for one database
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Lets take an example
Lets say we are storing a customers info……
1. At physical level
Data is stored in blocks of memory
May be hidden from programmer too
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2. At logical level
Records described as attributes along with
its datatypes
3. At View level
User interacts with the GUI
unaware of the database
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References:http://beginnersbook.com/2015/04/levels-of-abstraction-in-dbms/
http://whatis.techtarget.com/definition/data-abstraction
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