Database MCQ Number 00877

Database MCQ Set 1

1. A _____ indicates an absent value that may exist but be unknown or that may not exist at all.
a) Empty tuple
b) New value
c) Null value
d) Old value

2. If the attribute phone number is included in the relation all the values need not be entered into the phone number column . This type of entry is given as
a) 0
b) –
c) Null
d) Empty space

3. The predicate in a where clause can involve Boolean operations such as and.The result of true and unknown is_______ false and unknown is _____ while unknown and unknown is _____
a) Unknown, unknown, false
b) True, false, unknown
c) True, unknown, unknown
d) Unknown, false, unknown

4.

 SELECT name
FROM instructor
WHERE salary IS NOT NULL;
Selects

a) Tuples with null value
b) Tuples with no null values
c) Tuples with any salary
d) All of the mentioned

5. In a employee table to include the attributes whose value always have some value which of the following constraint must be used ?
a) Null
b) Not null
c) Unique
d) Distinct

6. Using the ______ clause retains only one copy of such identical tuples.
a) Null
b) Unique
c) Not null
d) Distinct

7.

CREATE TABLE employee (id INTEGER,name VARCHAR(20),salary NOT NULL);
INSERT INTO employee VALUES (1005,Rach,0);
INSERT INTO employee VALUES (1007,Ross, );
INSERT INTO employee VALUES (1002,Joey,335);

Some of these insert statements will produce an error. Identify the statement.
a) Insert into employee values (1005,Rach,0);
b) Insert into employee values (1002,Joey,335);
c) Insert into employee values (1007,Ross, );
d) None of the mentioned

8. The primary key must be
a) Unique
b) Not null
c) Both Unique and Not null
d) Either Unique or Not null

9. You attempt to query the database with this command:

 SELECT nvl (100 / quantity, NONE)
     FROM inventory;

Why does this statement cause an error when QUANTITY values are null?
a) The expression attempts to divide by a null value
b) The data types in the conversion function are incompatible
c) The character string none should be enclosed in single quotes (‘ ‘)
d) A null value used in an expression cannot be converted to an actual value

10. The result of _____unknown is unknown.
a) Xor
b) Or
c) And
d) Not

Database MCQ Set 2

1. OLAP stands for
a) Online analytical processing
b) Online analysis processing
c) Online transaction processing
d) Online aggregate processing

2. Data that can be modeled as dimension attributes and measure attributes are called _______ data.
a) Multidimensional
b) Singledimensional
c) Measured
d) Dimensional

3. The generalization of cross-tab which is represented visually is ______ which is also called as data cube.
a) Two dimensional cube
b) Multidimensional cube
c) N-dimensional cube
d) Cuboid

4. The process of viewing the cross-tab (Single dimensional) with a fixed value of one attribute is
a) Slicing
b) Dicing
c) Pivoting
d) Both Slicing and Dicing

5. The operation of moving from finer-granularity data to a coarser granularity (by means of aggregation) is called a ________
a) Rollup
b) Drill down
c) Dicing
d) Pivoting

6. In SQL the cross-tabs are created using
a) Slice
b) Dice
c) Pivot
d) All of the mentioned

7.

{ (item name, color, clothes size), (item name, color), (item name, clothes size), (color, clothes size), (item name), (color), (clothes size), () }

This can be achieved by using which of the following ?
a) group by rollup
b) group by cubic
c) group by
d) none of the mentioned

8. What do data warehouses support?
a) OLAP
b) OLTP
c) OLAP and OLTP
d) Operational databases

9.

SELECT item name, color, clothes SIZE, SUM(quantity)
FROM sales
GROUP BY rollup(item name, color, clothes SIZE);

How many grouping is possible in this rollup?
a) 8
b) 4
c) 2
d) 1

10. Which one of the following is the right syntax for DECODE ?
a) DECODE (search, expression, result [, search, result]… [, default])
b) DECODE (expression, result [, search, result]… [, default], search)
c) DECODE (search, result [, search, result]… [, default], expression)
d) DECODE (expression, search, result [, search, result]… [, default])

Database MCQ Set 3

1. In ordered indices the file containing the records is sequentially ordered, a _____ is an index whose search key also defines the sequential order of the file.
a) Clustered index
b) Structured index
c) Unstructured index
d) Nonclustered index

2. Indices whose search key specifies an order different from the sequential order of the file are called _____ indices.
a) Nonclustered
b) Secondary
c) All of the mentioned
d) None of the mentioned

3. An ______ consists of a search-key value and pointers to one or more records with that value as their search-key value.
a) Index entry
b) Index hash
c) Index cluster
d) Index map

4. In a _______ clustering index, the index record contains the search-key value and a pointer to the first data record with that search-key value and the rest of the records will be in the sequential pointers.
a) Dense
b) Sparse
c) Straight
d) Continuous

5. In a ____ index, an index entry appears for only some of the search-key values.
a) Dense
b) Sparse
c) Straight
d) Continuous

6. Incase the indices values are larger, index is created for these values of index. This is called
a) Pointed index
b) Sequential index
c) Multilevel index
d) Multiple index

7. A search key containing more than one attribute is referred to as a ___ search key.
a) Simple
b) Composite
c) Compound
d) Secondary

8. In B+ tree the node which points to another node is called
a) Leaf node
b) External node
c) Final node
d) Internal node

9. Insertion of a large number of entries at a time into an index is referred to as ____ of the index.
a) Loading
b) Bulk insertion
c) Bulk loading
d) Increase insertion

10. While inserting the record into the index, if the search-key value does not appear in the index.
a) The system adds a pointer to the new record in the index entry
b) The system places the record being inserted after the other records with the same search-key values
c) The system inserts an index entry with the search-key value in the index at the appropriate position
d) None of the mentioned

Database MCQ Set 4

1. A(n) ___ can be used to preserve the integrity of a document or a message.
a) Message digest
b) Message summary
c) Encrypted message
d) None of the mentioned

2. A hash function must meet ________ criteria.
a) Two
b) Three
c) Four
d) None of the mentioned

3. What is the main limitation of Hierarchical Databases?
a) Limited capacity (unable to hold much data)
b) Limited flexibility in accessing data
c) Overhead associated with maintaining indexes
d) The performance of the database is poor

4. The property (or set of properties) that uniquely defines each row in a table is called the:
a) Identifier
b) Index
c) Primary key
d) Symmetric key

5. The separation of the data definition from the program is known as:
a) Data dictionary
b) Data independence
c) Data integrity
d) Referential integrity

6. In the client / server model, the database:
a) Is downloaded to the client upon request
b) Is shared by both the client and server
c) Resides on the client side
d) Resides on the server side

7. The traditional storage of data that is organized by customer, stored in separate folders in filing cabinets is an example of what type of ‘database’ system?
a) Hierarchical
b) Network
c) Object oriented
d) Relational

8. The database design that consists of multiple tables that are linked together through matching data stored in each table is called
a) Hierarchical database
b) Network database
c) Object oriented database
d) Relational database

9. The association role defines:
a) How tables are related in the database
b) The relationship between the class diagram and the tables in the database
c) The tables that each attribute is contained
d) Which attribute is the table’s primary key

10. The purpose of an N-Ary association is:
a) To capture a parent-child relationship
b) To deal with one to many relationships
c) To deal with relationships that involve more than two tables
d) To represent an inheritance relationship

Database MCQ Set 5

1. Which of the following is a physical storage media ?
a) Tape Storage
b) Optical Storage
c) Flash memory
d) All of the mentioned

2. The ___ is the fastest and most costly form of storage, which is relatively small; its use is managed by the computer system hardware.
a) Cache
b) Disk
c) Main memory
d) Flash memory

3. Which of the following stores several gigabytes of data but usually lost when power failure?
a) Flash memory
b) Disk
c) Main memory
d) Secondary memory

4. The flash memory storage used are
a) NOR Flash
b) OR Flash
c) AND Flash
d) All of the mentioned

5. ____ is increasingly being used in server systems to improve performance by caching frequently used data, since it provides faster access than disk, with larger storage capacity than main memory.
a) Flash memory
b) Disk
c) Main memory
d) Secondary memory

6. Which is the cheapest memory device in terms of costs/bit ?
a) Semiconductor memory
b) Magnetic disks
c) Compact disks
d) Magnetic tapes

7. The primary medium for the long-term online storage of data is the ____ where the entire database is stored on magnetic disk.
a) Semiconductor memory
b) Magnetic disks
c) Compact disks
d) Magnetic tapes

8. Optical disk _______ systems contain a few drives and numerous disks that can be loaded into one of the drives automatically (by a robot arm) on demand.
a) Tape Storage
b) Jukebox
c) Flash memory
d) All of the mentioned

9. There are “record-once” versions of compact disk and digital video disk, which can be written only once; such disks are also called ____ disks.
a) Write-once, read-many (WORM)
b) CD-R
c) DVD-W
d) CD-ROM

10. Tape storage is referred to as ____ storage.
a) Direct-access
b) Random-access
c) Sequential-access
d) All of the mentioned

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