Computer Science - IT MCQs
Topic Notes: Computer Science - IT
<p>MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.</p>
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
491
Which database professional is primarily responsible for designing and implementing the database?
Answer:
Database Designer
The Database Designer is responsible for identifying the data to be stored and for choosing appropriate structures to represent and store this data. The DBA is more focused on managing the database system after it has been designed.
492
Which database function allows you to define the data your database stores?
Answer:
Data dictionary
While the Data Definition Language (DDL) is used to define the structure, the data dictionary stores these definitions and metadata about the database.
493
Which of the following is an example of an RDBMS?
Answer:
MySQL
MySQL is a popular open-source relational database management system that uses structured query language (SQL). MongoDB, Cassandra, and Redis are examples of NoSQL databases, which use different data models.
494
What tool would you use in a database to find answers to your questions about data?
Answer:
Queries
Queries are requests used to retrieve specific data from a database based on defined criteria or questions.
495
A data anomaly caused by data redundancy where updating a value requires changing it in multiple places is a(n):
Answer:
Update anomaly
An update anomaly occurs when a single piece of real-world information is stored in multiple rows. If this information is updated, all corresponding rows must be changed. Failing to update all rows leads to data inconsistency.
496
The `COMMIT` and `ROLLBACK` commands, which manage database transactions, are part of which SQL sub-language?
Answer:
TCL
TCL stands for Transaction Control Language. These commands are used to manage transactions in the database, ensuring they are completed successfully (`COMMIT`) or undone (`ROLLBACK`).
497
What is the primary purpose of the `GROUP BY` clause in a `SELECT` statement?
Answer:
To arrange rows into groups based on the values in one or more columns.
The `GROUP BY` clause is often used with aggregate functions (like `COUNT`, `MAX`, `SUM`) to group the result-set by one or more columns, allowing you to perform calculations on each group.
498
What is the highest level in the hierarchy of data organization?
Answer:
Data base
The database represents the highest level in the data hierarchy. It is a comprehensive collection that logically contains all the related files, which in turn contain records, fields, and so on.
499
Which of the following is NOT a relational DBMS?
Answer:
Reflex
While dBase IV, 4th Dimension, and FoxPro are all examples of relational database management systems, Reflex was an early flat-file database manager and not a relational one.
500
An ad hoc query is best described as what?
Answer:
Spur-of-the-moment question
Ad hoc queries are created on demand to answer a specific, often one-time question, without being pre-defined in the system.