Noorul Islam University 2008 M.Sc Software Engineering XCS 235 – DATABASE MANAGEMENT SYSTEMS - Question Paper

birth data attribute which is called stored attribute.
17. How are complex attributes represented?
Grouping components of a composite attribute ranging from paranthesis and
separating the components with commas and by displaying multivalued attributes
ranging from the braces {}. Such attributes are called complex attributes.
18. What is an entity type?
An entity kind describes a collection of entities that have the identical attributes.
19. What is an entity set?
The collection of all entities of a particular entity kind in the database at any point
in time is called an entity set.
20. What is a key attribute?
An entity kind usually has an attribute whose values are distinct for every
individual entity in the collection. Such an attribute is called a key attribute.
21. describe weak entity kind.
An entity kind may have no key; it is called weak entity kind.
22. describe valuesets of attributes.
It specifies the set of values that may be assigned to that attribute for every
individual entity.
23. describe degree of relationship kind
The degree of relationship kind is the number of participating entity kinds.
24. What is a role name?
The role name specifies the role that a participating entity from the entity kind
plays in every relationship.
25. elaborate the kinds of relationship constraints?
a) Cardinality ratio
b) Participation
26. describe cardinality ratio of binary relationship?
The cardinality ratio for a binary relationship specifies the number of relationship
instances that an entity can participate in.
27. describe participation constraint.
The participation constraint specifies whether the existence of an entity depends
on its being related to a different entity via the relationship kind.
28. elaborate the kinds of participation constraints?
a) Total participation
b) Partial participation
29. describe a partial key.
A weak entity kind has a partial key which is a set of attributes that can uniquely
identify weak entities that are related to the identical owner entity.
30. describe specialization.
Specialization is the process of defining a set of subclasses of an entity kind. This
entity kind is called the superclass of the specialization.
31. elaborate the main categories of storage hierarchy?
a) Primary storage

Earning:   Approval pending.