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Database Management System

Description: Oracle , SQL , Commands , ER - Diagrams
Number of Questions: 26
Created by:
Tags: SQL Oracle Databases
Attempted 0/26 Correct 0 Score 0

In which types of files does multimedia database store?

  1. HTTP

  2. Hypermedia files

  3. HTML files

  4. None of these


Correct Option: C
Explanation:

HTML files are not context dependent and by default, these are linked to browser.

Which one of the following steps is not involved in processing a query?

  1. Distribution

  2. Parsing and translation

  3. Optimizing

  4. Evaluation


Correct Option: A
Explanation:

 Distribution is dividing the data fields to their respectives, but query processing does not allow any kind of distribution. Query processing allows optimizing, evaluation and parsing and translation.

When do we use rollback of transaction?

  1. To repeat the transaction

  2. To update transaction

  3. To save all transactions

  4. To recover from transaction failure


Correct Option: D
Explanation:

Rollback is used to recover from transaction failure. We make savepoints, like checkpoints to save our transactions.

Which of the following is true by means of 5NF?

  1. Transitive dependency

  2. Multivalued dependency

  3. Join dependency

  4. None of these


Correct Option: C
Explanation:

5NF is known as projection join normal form (PJ/NF) if R relation is join dependency.

Which of the following is true by means of 4NF?

  1. Join dependency

  2. Transitive dependency

  3. Multivalued dependency

  4. None of these


Correct Option: C
Explanation:

Relation is same as in BCNF but additionally, it has more than one multivalued dependencies.

Which of the following statements is true by the mean of BCNF?

  1. Not less join but dependency preserving

  2. Loss less join but not dependency preserving

  3. Loss less join and dependency preserving

  4. None of these


Correct Option: B
Explanation:

 For every functional dependency, X->Y in a set F of functional dependencies are over. Unfortunately, BCNF is not dependency preserving. Dependency preserving is not a condition for BCNF decomposition.

Which of the following is not true about the proper state of transaction?

  1. Aborted

  2. Commited

  3. Rollback

  4. Partially aborted


Correct Option: D
Explanation:

 A transaction can never be partially aborted or partially commited or partially terminated.

When can we say a statement is not an embedded SQL?

  1. If all query processing is performed by the database system

  2. Use of correct and exact syntax with respect to an SQL language embedded

  3. Embedded SQL must follow RDBMS rules

  4. Embedded SQL expression for database modifications always return a value


Correct Option: D
Explanation:

It is not compulsary for SQL expression to return a value.

Which of the following is used to represent the relationship betwen tables?

  1. Primary Key

  2. Secondary Key

  3. Foreign Key

  4. None of these


Correct Option: C
Explanation:

Foreign key stores the primary key of others tables and is used for relationship.

At which level of architecture for a database system is the ANSI/SPARC report proposed?

  1. Level 1

  2. Level 2

  3. Level 3

  4. None of these


Correct Option: C
Explanation:

The ANSI/SPARC is a three level architecture. This shows that a data model can be an external model (or view), a conceptual model, or a physical model. This is not the only way to look at data models, but it is an useful way, particularly when comparing models.

Which commands are used to check which users have which privileges over which objects?

  1. CASCADE and MVD

  2. GRANT and REVOKE

  3. COMMIT and ROLLBACK

  4. None of these


Correct Option: B
Explanation:

 GRANT and REVOKE control the privileges over the different objects.

Which key provides the basic tuple-level addressing mechanism in a relational system?

  1. Primary Key

  2. Candidate Key

  3. Super Key

  4. Foreign Key


Correct Option: B
Explanation:

 Candidate Key is the only system guranteed way of pin pointing some specific tuple by some candidate key value.

In which of the following models the SET concept is used?

  1. Network model

  2. Hierarchical model

  3. Relational model

  4. None of these


Correct Option: A
Explanation:

 A data type as used in a typical relational database might be the set of integers. The popularity of the network data model coincided with the popularity of the hierarchical data model.Thus, the Network model uses SET .

How can we terminate a transaction, if the transaction is initiated by BEGIN TRANSACTION?

  1. COMMIT TRANSACTION

  2. ROLL BACK TRANSACTION

  3. (1) or (2)

  4. None of these


Correct Option: C
Explanation:

To SAVE and EXIT from the transaction, we should write COMMIT, or if we have made savepoint, then we have revert back then, make SAVEPOINT. So,  we can make either COMMIT or SAVEPOINT according to the query.

Which of the following keys should be one or more than one in a table?

  1. Candidate key

  2. Super key

  3. Primary key

  4. Both (1) and (2)


Correct Option: D
Explanation:

Candidate keys are special subsets of superkeys that do not have any extraneous information in them. Each table may have one or more candidate keys. A superkey is a combination of attributes that can be uniquely used to identify a database record. A table might have many superkeys. Hence, both the options 1 and 2 are correct.

Which of the following operations is used to construct the complex entries?

  1. Union

  2. NESTED IF

  3. AGGREGATION

  4. None of these


Correct Option: C
Explanation:

 Data aggregation is when the data is accrued, possibly from various sources.

What do we call a view of a database that appears in an application program?

  1. Schema

  2. Database instance

  3. Sub-schema

  4. All of the above


Correct Option: C
Explanation:

View is like a window to the table in the database or of the database, through which we can see the database. VIEW is a command to make a view of some essential attributes or columns of a database or table, so it is also called a sub-schema.

Which of the following statements is false?

  1. The conceptual level is a level of indirection.

  2. The conceptual view is a view of the total database content.

  3. All the data are not atomic

  4. A view is a named table having independent existence of its own


Correct Option: D
Explanation:

This is false. View has no independent existence. It is a virtual table.

By which integrity rule does the number key attribute of a row may be null?

  1. Referential integrity rule

  2. Distinct rows in a table

  3. Entity integrity rule

  4. None of these


Correct Option: C
Explanation:

(A Primary Key or part of it can not be null) - the rule says that 'null' is a special value in a relational database and it does not mean blank or zero.

How can we resolve the problem of data concurrency?

  1. Redundancy

  2. Versioning

  3. Transition

  4. None of these


Correct Option: B
Explanation:

Versioning involves recording and managing changes to a multi-user GEO database by creating a 'version' of the database—an alternative, independent, persistent view of the database that does not involve in creating a copy of the data and supports multiple concurrent.

What will happen if the union of primary keys of the related entity sets?

  1. It becomes super key.

  2. It becomes candidate key.

  3. It becomes foreign key.

  4. It becomes primary key


Correct Option: A
Explanation:

 A superkey is a combination of attributes that can be uniquely used to identify a database record. A table might have many superkeys.

How do we produce the relation that has attributes of X1 and X2?

  1. Difference

  2. Projection

  3. Natural join

  4. Cartesian product


Correct Option: D
Explanation:

The cartesian product of two tables combines each row in one table with each row in the other table.

Who is reponsible for ensuring that the database remains in a consistent state despite system failure?

  1. Transaction manager

  2. End user

  3. Storage manager

  4. None of these


Correct Option: A
Explanation:

System failures are detected by transaction manager. They also maintain the state of the base prior to failure.

What provides fast access to an arbitary record of a file in a file organization?

  1. Unordered file

  2. Ordered file

  3. Hash file

  4. None of these


Correct Option: C
Explanation:

Fast access is the main advantage of the hash file by indexing concept and it searches through the indexes.

Suppose X entity is associated with any number of entities in Y, however, entity Y is associated with almost 1 entity in X. What is the relation between X and Y?

  1. Many to many

  2. Many to one

  3. One to many

  4. None of these


Correct Option: C
Explanation:

X associated to any number of Y but Y is associated with only one entity of X , so relationship is one to many.

Which of the following operations will increase the length of the list?

  1. Update

  2. Modify

  3. Insert

  4. All of the above


Correct Option: C
Explanation:

Insert is used to insert a new row in a table - like insert in to table values (data1 , XYZ ) ; and length of the list is directly proportional to the insertion made.

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