DATABASE MANAGEMENT SYSTEM:SOLVED MODEL TEST PAPER FOR UGC NET COMPUTER SCIENCE DECEMBER 2013
1. What is meant by functional dependency.
Functional dependency is the relationship between attributes such that the value of an attribute is determined by value of another attribute.
Example: Regno->Name (Functional Dependency)
That is, 'Name' is dependent on the attribute 'Regno'.
In this case, Regno is a primary key.
2. What is meant by transitive dependency.
Transitive dependency occurs when a non key attribute value is functionally dependent on another non key attribute.
Example: Empid->Jobtype
Jobtype->Hourpay
In this case, Jobtype is dependent on Empid.
In the second case, Hourpay is dependent on Jobtype, which is a non key attribute.
Therefore, when a non key attribute is dependent on another non key attribute, it is called as transitive dependency.
Note: In Database Management System, dependencies are not required. So we go for NORMALIZATION
to reduce dependencies.
1. What is meant by functional dependency.
Functional dependency is the relationship between attributes such that the value of an attribute is determined by value of another attribute.
Example: Regno->Name (Functional Dependency)
That is, 'Name' is dependent on the attribute 'Regno'.
In this case, Regno is a primary key.
2. What is meant by transitive dependency.
Transitive dependency occurs when a non key attribute value is functionally dependent on another non key attribute.
Example: Empid->Jobtype
Jobtype->Hourpay
In this case, Jobtype is dependent on Empid.
In the second case, Hourpay is dependent on Jobtype, which is a non key attribute.
Therefore, when a non key attribute is dependent on another non key attribute, it is called as transitive dependency.
Note: In Database Management System, dependencies are not required. So we go for NORMALIZATION
to reduce dependencies.
