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Database Management System MCQs

749+ questions with answers

451

To identify the deleted records we use the ______________

a Existence bitmap
b Current bitmap
c Final bitmap
d Deleted bitmap
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452

Bitmaps can be used as a compressed storage mechanism at the leaf nodes of ________ for those values that occur very frequently.

a B-trees
b B+-trees
c Bit trees
d Both B-trees and B+-trees
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453

Bitmaps can be combined with regular B+-tree indices for relations where a few attribute values are extremely common, and other values also occur, but much less frequently.

a Bitmap, B-tree
b Bitmap, B+tree
c B-tree, Bitmap
d B+tree, Bitmap
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454

A tablespace is further broken down into ________

a Tablespace
b Segments
c Extents
d Blocks
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455

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
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456

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
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457

What is the purpose of the index in sql server?

a To enhance the query performance
b To provide an index to a record
c To perform fast searches
d All of the mentioned
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458

How many types of indexes are there in sql server?

a 1
b 2
c 3
d 4
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459

How non clustered index point to the data?

a It never points to anything
b It points to a data row
c It is used for pointing data rows containing key values
d None of the mentioned
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460

Which one is true about clustered index?

a Clustered index is not associated with table
b Clustered index is built by default on unique key columns
c Clustered index is not built on unique key columns
d None of the mentioned
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461

What is true about indexes?

a Indexes enhance the performance even if the table is updated frequently
b It makes harder for sql server engines to work to work on index which have large keys
c It doesn’t make harder for sql server engines to work to work on index which have large keys
d None of the mentioned
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462

Does index take space in the disk?

a It stores memory as and when required
b Yes, Indexes are stored on disk
c Indexes are never stored on disk
d Indexes take no space
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463

If an index is _________________ the metadata and statistics continue to exists

a Disabling
b Dropping
c Altering
d Both Disabling and Dropping
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464

In _______________ index instead of storing all the columns for a record together, each column is stored separately with all other rows in an index.

a Clustered
b Column store
c Non clustered
d Row store
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465

A _________________ index is the one which satisfies all the columns requested in the query without performing further lookup into the clustered index.

a Clustered
b Non Clustered
c Covering
d B-Tree
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466

A collection of data designed to be used by different people is called a/an

a Organization
b Database
c Relationship
d Schema
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467

Which of the following is the oldest database model?

a Relational
b Deductive
c Physical
d Network
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468

Which of the following schemas does define a view or views of the database for particular users?

a Internal schema
b Conceptual schema
c Physical schema
d External schema
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469

Which of the following is an attribute that can uniquely identify a row in a table?

a Secondary key
b Candidate key
c Foreign key
d Alternate key
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470

Which of the following are the process of selecting the data storage and data access characteristics of the database?

a Logical database design
b Physical database design
c Testing and performance tuning
d Evaluation and selecting
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471

Which of the following terms does refer to the correctness and completeness of the data in a database?

a Data security
b Data constraint
c Data independence
d Data integrity
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472

A table can be logically connected to another table by defining a

a Super key
b Candidate key
c Primary key
d Unique key
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473

If the state of the database no longer reflects a real state of the world that the database is supposed to capture, then such a state is called

a Consistent state
b Parallel state
c Durable state
d Inconsistent state
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474

Ensuring isolation property is the responsibility of the

a Recovery-management component of the DBMS
b Concurrency-control component of the DBMS
c Transaction-management component of the DBMS
d Buffer management component in DBMS
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475

In query processing, the ___________ is the lowest-level operator to access data.

a Index Search
b Linear search
c File scan
d Access paths
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476

In a ____________ the system scans each file block and tests all records to see whether they satisfy the selection condition.

a Index Search
b Linear search
c File scan
d Access paths
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477

Index structures are referred to as __________ since they provide a path through which data can be located and accessed.

a Index Search
b Linear search
c File scan
d Access paths
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478

Search algorithms that use an index are referred to as

a Index Search
b Linear search
c File scan
d Access paths
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479

Which algorithm uses equality comparison on a key attribute with a primary index to retrieve a single record that satisfies the corresponding equality condition.

a A2
b A4
c A5
d A6
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480

The strategy can retrieve a single record if the equality condition is on a key; multiple records may be retrieved if the indexing field is not a key is

a A2
b A4
c A5
d A6
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481

The ___ algorithm scans each index for pointers to tuples that satisfy an individual condition.

a A2
b A4
c A9
d A6
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482

If access paths are available on all the conditions of a disjunctive selection, each index is scanned for pointers to tuples that satisfy the individual condition. This is satisfied by

a A10
b A7
c A9
d A6
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483

Conjunctive selection using one index. This is

a A10
b A7
c A9
d A6
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484

Two main measures for the efficiency of an algorithm are

a Processor and memory
b Complexity and capacity
c Time and space
d Data and space
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485

The time factor when determining the efficiency of an algorithm is measured by

a Counting microseconds
b Counting the number of key operations
c Counting the number of statements
d Counting the kilobytes of algorithm
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486

The space factor when determining the efficiency of an algorithm is measured by

a Counting the maximum memory needed by the algorithm
b Counting the minimum memory needed by the algorithm
c Counting the average memory needed by the algorithm
d Counting the maximum disk space needed by the algorithm
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487

Which of the following case does not exist in complexity theory

a Best case
b Worst case
c Average case
d Null case
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488

The Worst case occur in linear search algorithm when

a Item is somewhere in the middle of the array
b Item is not in the array at all
c Item is the last element in the array
d Item is the last element in the array or is not there at all
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489

The Average case occur in linear search algorithm

a When Item is somewhere in the middle of the array
b When Item is not in the array at all
c When Item is the last element in the array
d When Item is the last element in the array or is not there at all
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490

The complexity of a linear search algorithm is

a O(n)
b O(log n)
c O(n2)
d O(n log n)
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491

The complexity of Binary search algorithm is

a O(n)
b O(log )
c O(n2)
d O(n log n)
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492

The complexity of Bubble sort algorithm is

a O(n)
b O(log n)
c O(n2)
d O(n log n)
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493

A_____ is a query that retrieves rows from more than one table or view:

a Start
b End
c Join
d All of the mentioned
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494

A condition is referred to as __________

a Join in SQL
b Join condition
c Join in SQL & Condition
d None of the mentioned
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495

Which oracle is the join condition is specified using the WHERE clause:

a Oracle 9i
b Oracle 8i
c Pre-oracle 9i
d Pre-oracle 8i
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496

How many join types in join condition:

a 2
b 3
c 4
d 5
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497

Which are the join types in join condition:

a Cross join
b Natural join
c Join with USING clause
d All of the mentioned
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498

Which product is returned in a join query have no join condition:

a Equijoins
b Cartesian
c Both Equijoins and Cartesian
d None of the mentioned
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499

Which join refers to join records from the write table that have no matching key in the left table are include in the result set:

a Left outer join
b Right outer join
c Full outer join
d Half outer join
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500

Which operation are allowed in a join view:

a UPDATE
b INSERT
c DELETE
d All of the mentioned
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