Database Management System Set 28

Database Management System

Questions 271 to 280


271.
When converting one (1) to many (N) binary relationship into tables, the recommended solution is usually
(a)
One big table with all attributes from both entities included
(b)
Foreign key added on the Child (many side) referencing the parent
(c)
Foreign key added on the Parent (one side) referencing the child
(d)
Foreign key added on both sides (both tables)            
(e)
Primary Key is added on one side.
272.
Which of the following is not correct?
(a)
Each entity must include some descriptive information
(b)
If an object only requires an identifier, it should be classified as an attribute
(c)
Each multivalued attribute should be classified as an entity even if it does not have any descriptive information
(d)
The procedure of identifying entities and attaching attributes always leads to a unique solution
(e)
Every entity is a collection of attributes.
273.
The property of transaction which ensures that either all operations of the transaction are reflected properly in the database or none, is called
(a)
Atomicity
(b)
Durability
(c)
Isolation
(d)
Consistency
(e)
Deadlock.
274.
Which of the following is correct?
(a)
Function dependencies are not associated with relations; they are based on the semantics of information that we are dealing with
(b)
If a relation has no redundant information its attributes must not have any function dependencies
(c)
Functional dependencies may be determined if we are given several instances of a relation
(d)
The FDs that hold for attributes of a relation need not be satisfied at all times
(e)
BCNF is a fourth normal form.
275.
An entity type whose existence depends on another entity type is called a _____ entity.
(a)
Strong
(b)
Weak
(c)
Codependent
(d)
Variant
(e)
Independent.
276.
A property or characteristic of an entity type that is of interest to the organization is called an
(a)
Attribute
(b)
Coexisting entity
(c)
Relationship
(d)
Cross-function
(e)
Weak entity.
277.
A relationship between the instances of a single entity type is called a _____ relationship.
(a)
Ternary
(b)
Primary
(c)
Binary
(d)
Auxiliary
(e)
Unary.
278.
A ________ attribute is an attribute that can be further subdivided to yield additional attributes.
(a)
Composite
(b)
Simple
(c)
Single-valued
(d)
Multi-valued
(e)
Derived.
279.
In a super type/subtype hierarchy, each subtype has
(a)
Only one super type
(b)
Many super types
(c)
At most two super types
(d)
At least one subtype
(e)
Not at all.
280.
The hierarchical database model uses the hierarchic sequence that always starts at
(a)
The right side of the tree
(b)
The left side of the tree
(c)
The top of the tree
(d)
The bottom of the tree
(e)
Middle of the above.

Answers



271.
Answer : (b)
Reason:  When converting one (1) to many (N) binary relationship into tables, the recommended solution is Foreign key added on the Child (many side) referencing the parent
272.
Answer : (d)
Reason:  The procedure of identifying entities and attaching attributes always leads to a unique solution
273.
Answer : (a)
Reason:  Atomicity is the property of transaction which ensures that either all operations of the transaction are reflected properly in the database or none
274.
Answer : (a)
Reason:  Function dependencies are not associated with relations; they are based on the semantics of information that we are dealing with.
275.
Answer : (b)
Reason:  Entity type whose existence depends on another entity type is called a weak entity
276.
Answer : (a)
Reason:  A property or characteristic of an entity type that is of interest to the organization is called attribute
277.
Answer : (e)
Reason:  A relationship between the instances of a single entity type is called a Unary relationship.
278.
Answer : (a)
Reason:  Composite attribute is an attribute that can be further subdivided to yield additional attributes.
279.
Answer : (a)
Reason:  In a super type/subtype hierarchy, each subtype has only one super type
280.
Answer : (b)
Reason:  The hierarchical database model uses the hierarchic sequence that always starts at the left side of the tree
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