abstractions in dbms

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Abstractions in DBMS

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Page 1: Abstractions in DBMS

Abstractions in DBMS

Page 2: Abstractions in DBMS



Page 3: Abstractions in DBMS

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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