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
11
Which of the following is not a feature of a DBMS?
Answer:
Data redundancy
A key objective of a DBMS is to control and minimize data redundancy (the unnecessary duplication of data). Data consistency, security, and integrity are all important features that a DBMS provides to manage data effectively.
12
The process of managing simultaneous operations on the database without them interfering with each other is known as:
Answer:
Concurrency Control
Concurrency control is a crucial function of a DBMS. It ensures that when multiple transactions are executed concurrently, the results are the same as if they were executed sequentially, thereby preventing data inconsistencies.
13
A constraint that is defined at the column level applies to:
Answer:
Only that specific column.
A column-level constraint is part of the column's definition and only applies to that column. A table-level constraint is declared separately and can apply to one or more columns in the table (e.g., a composite primary key).
14
A person's phone numbers would be an example of what kind of attribute?
Answer:
Multivalued
Since a single person can have more than one phone number (e.g., home, mobile, work), the `PhoneNumber` attribute would be classified as a multivalued attribute.
15
Although it deletes all rows, the `TRUNCATE` command is categorized as a DDL statement rather than a DML statement. Why?
Answer:
All of the above.
`TRUNCATE` is considered DDL because it often operates differently from `DELETE`. It usually cannot be rolled back, it resets auto-incrementing identity columns (modifying the table's structure implicitly), and is generally a more privileged, impactful operation.
16
A key that consists of more than one attribute to uniquely identify a record is called a:
Answer:
Composite Key
A composite key, also known as a compound key, is a type of primary key that consists of two or more columns in a table that, together, uniquely identify each record.
17
Which of the following is NOT a typical function of a Database Administrator (DBA)?
Answer:
Writing application logic for end-users
While a DBA manages the database system, writing the specific application logic for end-user programs is typically the responsibility of an Application Programmer, not the DBA.
18
The smallest logical unit of data that has meaning to a user, such as a name or a price, is a:
Answer:
Field
In the data hierarchy, a field (or attribute) represents a single piece of information about an entity. Multiple fields are grouped together to form a record.
19
The software that allows users to define, create, maintain, and control access to the database is called a:
Answer:
Database Management System (DBMS)
This is the definition of a DBMS. It acts as an interface between the user/application and the physical database, simplifying data management tasks.
20
If the same data is stored in two places in a database:
Answer:
Both A and B
Storing the same data in multiple locations is known as data redundancy. This practice wastes valuable storage space and creates a significant risk of data inconsistency, where an update in one location might not be reflected in the other, leading to conflicting information.