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A model in database system mostly defines the organisation of data or structure and a set of operations on that data. Relational model is a easy model in which database is represented as a collection of "Relations", where every relation is represented by a two dimensional table. Therefore, because of its simplicity it is most commonly used. The following table shows a simple relation:
PERSON_ID
NAME
AGE
ADDRESS
1
Sanjay Prasad
35
b-4,Modi Nagar
2
Sharad Gupta
30
Pocket 2, Mayur
Vihar.
3
Vibhu Datt
36
c-2, New Delhi
Figure: A Sample Person Relation
Following are some of the benefits of relational model:
The easy tabular representation of database helps the user define and question the database conveniently. For example, you can simply find out the age of the person whose first name is "Vibhu".
As the database is a collection of tables, new data can be added and removed easily. Also, manipulation of data from several tables can be done simply using several basic operations. For instance, we can add a telephone number field in the table at Figure.
In relational databases the relational algebraic operations are used to influence database. These are mathematical operations and make sure accuracy (and less of ambiguity) as compared to other models.
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An entity set that does not have sufficient attributes to form a primary key is called? An entity set that doesn't have sufficient attribute to form a primary key is known as w
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