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
4661
The `HAVING` clause is used in conjunction with which other clause?
Answer:
GROUP BY
The `HAVING` clause was added to SQL because the `WHERE` keyword could not be used with aggregate functions. `HAVING` is used to filter groups created by the `GROUP BY` clause.
4662
Which function in an organization plans for information resources?
Answer:
Data administration
Data administration involves the high-level planning, policy-making, and management of an organization's data resources.
4663
Which is a smaller, more focused section of a data warehouse?
Answer:
Data mart
A data mart is a subset of a data warehouse that is designed for the specific needs of a particular business line or department.
4664
A functional dependency, denoted as A -> B, means that:
Answer:
The value of attribute B is uniquely determined by the value of attribute A.
A functional dependency exists between two attributes, A (the determinant) and B, if for every valid value of A, that value of A uniquely determines the value of B.
4665
To use a record management system, you need to understand:
Answer:
The model the record management system uses
To interact with a record management system effectively, a user needs to understand its logical model—how it organizes and relates data. The system is designed to hide the complex low-level physical storage details from the user.
4666
Which of the following is a common denormalization technique?
Answer:
Storing derivable values.
Storing derivable values (e.g., pre-calculating a total and storing it in a column instead of calculating it at query time) is a common denormalization strategy to avoid complex calculations and improve query speed.
4667
What is a CHECK constraint?
Answer:
It ensures that the values in a column satisfy a specific condition.
A CHECK constraint is used to enforce domain integrity by limiting the values that are accepted by a column. It validates the data against a specified condition before allowing it to be stored.
4668
Which database key uniquely identifies a record in a table?
Answer:
Primary key
A primary key is a specific choice of a minimal set of attributes (columns) that uniquely specify a tuple (row) in a table.
4669
Which data model is the most widely used today?
Answer:
Relational model
Despite the rise of NoSQL databases, the relational model remains the most dominant and widely used data model for a vast range of applications, forming the foundation for popular databases like MySQL, PostgreSQL, Oracle, and SQL Server.
4670
The main goal of designing a database in 3NF is to:
Answer:
Eliminate transitive dependencies of non-prime attributes on the primary key.
While 1NF handles atomicity and 2NF handles partial dependencies, the specific goal of moving from 2NF to 3NF is to remove transitive dependencies, ensuring that all non-key attributes are dependent only on the primary key and not on other non-key attributes.