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

To be considered minimally relational, the DBMS must support of the following key relational functions.

  1. SELECT, PROJECT, UNION

  2. SELECT, PROJECT, JOIN

  3. SELECT, UNION, JOIN

  4. SELECT, UNION, INTERSECT
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Relational algebra defines the theoretical way of manipulating table contents using the eight relational functions. To be considered minimally relational, the DBMS must support the key relational functions SELECT, PROJECT and JOIN.

Multiple choice

Find the odd man out.

  1. Desktop database

  2. Work group database

  3. Distributed database

  4. Enterprise database
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Desktop database, workgroup database and enterprise database is the classification of DBMS according to number of users where a distributed DBMS is classification according to database site location.

Multiple choice

Database that are designed and managed specifically to meet information needs are called

  1. production databases

  2. transaction database

  3. data warehouses

  4. database management system
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Production database are also known as transaction databases. Although such database yield streams of useful information, there are specialized databases, known as data warehouses that are designed and managed specifically to meet information needs. The data warehouses derive their data from production databases.

Multiple choice

A file system is said to exhibit data dependence, because

  1. a change in any file's structure such as the addition or deletion of a field, requires the modification of all programs using that file

  2. organization of the data, within the file is determined by the data's expected use

  3. data is the most important part of a file system, which also includes hardware software, people and procedures

  4. when any of the files data characteristics change, all data access programs are subjects to change
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A file system is said to exhibit structural dependence because a change in any file's structure such as addition or deletion of a field, requires modification of all programs using that file. That means access to a file is dependent on its structure.

Multiple choice

The data retrieval time factor is most critical for

  1. transactional DBMS

  2. decision DBMS

  3. data warehouse

  4. both (2) and (3)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Transactions such as product or service sates payments and supply purchases reflect critical day to day operations such transactions are time critical and must be recorded accurately and immediately.

Multiple choice

Which of the following is not supported by the hierarchical database model?

  1. Structural independence

  2. Data independence

  3. Database integrity

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

The most important advantages of hierarchical models are conceptual simplicity, database security, data independence, database integrity and efficiency. Hierarchical database model lacks structural independence.

Multiple choice

If the solution of the previous question was the log at the time of crash, then what will be the output of A, B and C after recovery?

  1. A = 1050 B = 2055 C = 720

  2. A = 957 B = 2055 C = 720

  3. A = 957 B = 2055 C = 640

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the system comes back, the operation redo to is performed since the record. Appears in the log on the disk after this operation is executed, the values of account A and B are $957 and $2055, respectively. The value of account C remains $720 because T1 has not been committed yet.

Multiple choice

Consider the following transaction T0 and T1<To start><To , A, 1050, 970><To, B, 2030, 2070><To commit><T1 start><T1, C, 720,640><T1 commit> If the system crashes just after log record for the step write C of transaction T1 has been written to stable storage, the log at the time of crash will be

  1. <T0 start> <T0, A, 935><T0, B, 2055>

  2. <T0 start><T0, A, 957><T0, B, 2055><T0 commit><T1 start><T1, C, 640>

  3. <T0 start><T0, A, 957><T0, B, 2055><T0 commit><T1 start><T1, C, 62><T1, Commit>

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The log at the time of crash will be option B, which reaches up to commit statement but not including commit statement. Option (2) gives the correct log at the time of crash.

Multiple choice

Which of the following queries finds the clients of banker Agassi and the city they live in?
  1. $\pi_{client, customer\ name, customer\ city} (\sigma_{Banker name} = “Agassi” (client × customers))$
  2. $\pi_{client, customer\ name, customer\ city} (\sigma_{Banker name} = “Agassi” (client × customers)$
  3. $\pi_{client, customer\ name, customer\ city} \\\\ (\sigma_{Banker name} = “Agassi” (\sigma_{client} × customer name) = \\\\ customer, customer\ name (client × customers)$
  4. $\pi_{customer\ name, customer\ city }(\sigma_{Banker name} = “Agassi” (client × customers)$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The SQL statement is select client customer name, client customer city from client customer where (client customer name = customer. Customer name and banker name = “Agassi” $\therefore$Relational algebra query is$\pi_{client, customer\ name, customer\ city} (\sigma_{Client, customer\ name})= customer. customer name \\ (\sigma_{Banker name} = “Agassi” (client × customers)$

Multiple choice

Which of the following does the database administrator coordinate?

  1. DBMS and data base

  2. Application program and data base

  3. Data base and users

  4. Application program and users
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The database administrator serves as the intermediary between the database system and its users, managing access, security, performance, and ensuring users can effectively utilize the database resources.

Multiple choice

A relational database, which is in 3NF, may have undesirable data redundancy because there may exist

  1. non-trivial functional dependencies involving prime attributes on the right side

  2. non -trivial functional dependencies involving only prime attributes

  3. either (1) or (2)

  4. both (1) and (2)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Third Normal Form (3NF) only eliminates transitive dependencies where non-prime attributes depend on other non-prime attributes. Functional dependencies involving prime attributes (either as determinant or dependent) can still exist and cause data redundancy even in 3NF relations.

Multiple choice

These are five records in a data base:

     
Name Age Occupation Category
Neha 23 CON A
Dhruti 24 ENG B
Sonika 25 DOC C
Poonam 26 SER D

There is an index file associated with this and it contains the values: 1, 3, 2, 4. Which of the following fields is the index built form?

  1. Age

  2. Name

  3. Occupation

  4. Category

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sorting records by Occupation alphabetically: CON(1), DOC(3), ENG(2), SER(4) gives the index order [1,3,2,4]. This matches the given index file values.