31) What Is Degree Of A Relation?
Answer: It is the number of attribute of its relation schema.
32) Discuss The Properties Of A Relation?
Answer: A relation has the following properties:
- Has a name that is distinct from all other relation names in the relational schema.
- Each cell contains exactly one atomic (single) value.
- Each attribute has a distinct name.
- The values of an attribute are all from the same domain.
- Each tuple is distinct; there are no duplicate tuples.
- The order of attributes has no significance.
- The order of tuples has no significance, theoretically.
33) What Is Relationship, Relationship Type & Relationship Set?
Answer: Relationship is an association among two or more entities. A relationship relates two or more distinct entities with a specific meaning.
For example, EMPLOYEE Rahul Jain works on the XXX PROJECT, or
EMPLOYEE Vineet Kumar manages the Finance DEPARTMENT.
Relationship type defines a set of associations or a relationship set among a given set of entity types. Relationships of the same type are grouped or typed into a relationship type.
For example, the WORKS_ON relationship type in which EMPLOYEEs and PROJECTs participate, or the MANAGES relationship type in which EMPLOYEEs and DEPARTMENTs participate.
Relationship set is a collection (or set) of similar relationships or say it is a set of relationship instances represented in the database.
34) What Is Degree Of Relationship Type?
Answer: The degree of a relationship type is the number of participating entity type. Both MANAGES and WORKS_ON are binary relationships.
35) What Is A Recursive Relationship TYPE?
Answer: Some relationships involve only one entity. Such a relationship is called Recursive Relationship.
Example: Consider a relationship between EMPLOYEE entity type. In the SUPERVISION relationship EMPLOYEE participates twice in two distinct roles:
- supervisor (or boss) role
- supervisee (or subordinate) role
- One employee in supervisor role
- One employee in supervisee role
ALSO CHECK THE BELOW FAQ's:
36) What Is An Extension Of Entity Type?
37) What Is Weak Entity Set?
38) What Is An Entity? Differentiate Between Strong & Weak Entity?
39) What Is An Attribute? What Are The Types Of Attributes?
40) Differentiate Between The Different Types Of Attributes?
41) Define The Types Of Data Integrity Rules?
42) What Is A Table? What Is A Tuple? What Is A Relation?
43) What Are Extension & Intension?
44) What Is A View? How It Is Related To Data Independence?
45) What Is A View? Discuss The Difference Between A View & A Base Relation?
... Return To DBMS FAQ's Main Page.
... Return To HR Interview Questions With Answers Main Page.