Computer Science/IT MCQs
Topic Notes: Computer Science/IT
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
191
What is the purpose of the `COMMIT` command?
Answer:
To permanently save a transaction.
The COMMIT command is a TCL command that finalizes a transaction, making all changes made during the transaction permanent in the database. Once a transaction is committed, it cannot be rolled back.
192
What does RDBMS stand for?
Answer:
Relational Database Management System
RDBMS is the acronym for Relational Database Management System. This type of DBMS is based on the relational model proposed by E. F. Codd, which organizes data into tables (relations) of rows and columns.
193
Generalized database management systems do not retrieve data for routine requests. (True/False)
Answer:
False
Generalized DBMS are designed to be flexible and powerful, capable of handling both routine, pre-defined requests and ad-hoc, spontaneous queries from users.
194
Which of the following best describes the core purpose and most encompassing objective of a Database Management System (DBMS)?
Answer:
Enabling efficient data retrieval and modification while ensuring data quality.
A Database Management System (DBMS) serves a multifaceted role, but its most encompassing objective, as reflected in option B, is to enable efficient organization, retrieval, and modification of data while simultaneously ensuring the data's quality, consistency, and reliability.
Let's analyze why other options are less appropriate:
* **Option A (Minimizing storage space by compressing data):** While data compression can be a feature of some DBMS implementations, it is a secondary optimization, not the core purpose. The primary goal is managing the data effectively, not just saving space.
* **Option B (Enabling efficient data retrieval and modification while ensuring data quality):** This option accurately captures the essence of a DBMS. It highlights both the operational aspects (efficient retrieval and modification) and the critical non-functional requirement (ensuring data quality, which encompasses integrity, consistency, and accuracy).
* **Option C (Converting physical data into digital formats for archival purposes):** This describes data digitization or archiving, which might involve a database, but it's not the primary function of a DBMS itself. A DBMS manages digital data, it doesn't primarily convert physical data.
* **Option D (Providing an exclusive interface for single-user data entry):** This is incorrect. DBMSs are specifically designed for multi-user access and concurrent operations, often providing various interfaces for different types of users and applications. Exclusive single-user access contradicts the fundamental utility of most modern DBMSs.
195
Which of the following is NOT a responsibility of a Database Administrator (DBA)?
Answer:
Writing application programs
Writing application programs that use the database is the responsibility of an Application Programmer or Software Developer. The DBA is responsible for the overall management, security, and performance of the database system.
196
What does the 'A' in the ACID properties of a transaction stand for?
Answer:
Atomicity
Atomicity ensures that a transaction is treated as a single, indivisible unit. Either all of its operations are executed successfully, or none of them are. This is often referred to as the "all-or-nothing" rule.
197
An attribute that is not part of any candidate key is called a...
Answer:
Non-prime attribute.
Attributes in a relation are classified into two types. A prime attribute is an attribute that is a part of at least one candidate key. A non-prime attribute is an attribute that is not a part of any candidate key.
198
What type of database provides multiple layers to tables for advanced analysis?
Answer:
Data warehouse
A data warehouse stores large volumes of historical data in multidimensional structures optimized for complex analysis and reporting, rather than transactional processing.
199
A relationship between instances of a single entity type is called a:
Answer:
Unary (or recursive) relationship
A unary or recursive relationship is one where instances of the same entity set participate. A common example is an 'Employee' entity where an employee can supervise other employees, creating a 'manages' relationship within the same entity.
200
The language used by application programs to request data from the DBMS is:
Answer:
DML
DML stands for Data Manipulation Language. It is the subset of a database language (like SQL) that application programs use to perform operations such as retrieving, inserting, updating, and deleting data from the database.