Wednesday, 15 February 2017

What is degree of relationship in ER modeling in dbms

What is degree of relationship in ER modeling in dbms, Define degree of relationship, examples for degree of relationship, degree of relationship type


Degree of relationship

Degree of relationship is the number of entity sets that are participated (associated) in that relationship. That is, the number of entity sets that are connected through the relationship in question is called the degree of relationship.
Based on the degree, the relationships may be identified as unary (degree 1), binary (degree 2), ternary (degree 3) and so on.
Below given the ER diagram that shows the degrees of relationships;
Unary relationship
 The relationship ‘Represents’ is an one-to-many Unary relationship. It connects with only one table (relation/entity set).
Binary relationship
 The relationship ‘Registers’ is a many-to-many Binary relationship. It connects (associates) two entity sets, Student and Courses.
Ternary relationship
The relationship ‘STC’ is a many-t-many Ternary relationship. It links the entity sets Student, Courses and Teacher.

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