Computer Knowledge

Database Management Systems

5,344 Questions

Database Management Systems (DBMS) form the core framework for data storage, retrieval, and security in modern software applications. Concepts such as the E-R model, backup planning, SQL integration, and big data architecture are essential for computer knowledge sections. This hub offers a comprehensive set of practice questions to master DBMS fundamentals and advanced database operations.

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Database Management Systems Questions

Multiple choice

A repository for data, usually covering some specific topic is called

  1. Data acquisition

  2. Data bank

  3. Database system

  4. Database
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A data bank is a large repository of information on a specific subject, often compiled from multiple sources. While the term database is more common in modern technical contexts, data bank specifically emphasizes the collection of data for a particular topic or field. Data acquisition refers to the process of gathering data, not the storage itself.

Multiple choice

Which of the following techniques is used for denormalisation in which the records are summarised in some summary columns and the number of records stored in a table is reduced?

  1. Vertical fragmentation

  2. Horizontal partitioning

  3. Summary data

  4. Duplicate data

  5. Functional dependency
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the technique used for denormalisation in which the records are summarised in some summary columns. It reduces the number of records stored in a table.

Multiple choice

Which of the following models is a specialised adaption of the relational model used to represent data in a data warehouse in a way that data can be easily summarised using OLAP queries?

  1. Object database

  2. Dimensional

  3. Post-relational database

  4. Network data

  5. Hierarchical data
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This model is a specialised adaption of the relational model. It is used to represent data in a data warehouse in a way that data can be easily summarised using OLAP queries.

Multiple choice

CDPD means

  1. cellular digital popular data

  2. cellular digital packet data

  3. complex digital packet data

  4. complex digital popular data
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CDPD stands for Cellular Digital Packet Data. It was a data transmission technology used on analog cellular networks (AMPS) in the 1990s. It allowed for packet-switched data to be sent during the idle periods of voice channels, providing an early form of mobile internet access.

Multiple choice

What is 'ISOLATION LEVEL SERIALIZE' parameter in SET TRANSACTION statement in PL/SQL?

  1. It is used to check the resource to be updated by multiple transactions.

  2. If a transaction requires row locks held by another transaction, the transaction will wait until the row locks are released.

  3. It assigns the transaction to a rollback segment identified by 'segment_name'.

  4. It assigns a name to the transaction identified by 'transaction_name'.

  5. Both (1) and (3)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If a transaction attempts to update a resource that has been updated by another transaction and uncommitted, the transaction will fail.

Multiple choice

Which of the following statements is/are incorrect about 'SAVEPOINT' clause in Rollback statement in PL/SQL?

  1. It is used to undo all the changes for the current session.

  2. It is used to force the rollback of a transaction that may be corrupt or in doubt.

  3. ROLLBACK TO SAVEPOINT savepoint 1 is the syntax for this clause.

  4. ROLLBACK WORK TO SAVEPOINT savepoint 1 is the syntax for this clause.

  5. Both (2) and (3)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is called 'FORCE' clause in Rollback statement.