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
4701
Which level of data abstraction describes *how* the data is actually stored on the storage device?
Answer:
Physical Level
The physical level is the lowest level of data abstraction and describes the complex low-level data structures and storage details. It defines how data is physically stored on disk.
4702
The relational database environment includes all the following except:
Answer:
Separate files
Modern relational databases use integrated structures to manage data holistically, not isolated or separate files for different parts of the data. This integrated approach is a key feature that distinguishes them from older file-based systems.
4703
Which term describes an organized collection of information designed for efficient storage, retrieval, and management?
Answer:
A database
A database is fundamentally a structured and organized collection of data. Its primary purpose is to allow for efficient access, retrieval, and use of this data. While spreadsheets can store data, they lack the sophisticated organization and management features of a database, especially for large and complex datasets. A document typically refers to a single file, and a directory is a system for organizing files, not the data within them.
4704
What is denormalization?
Answer:
The process of combining tables to increase data redundancy for performance.
Denormalization is a strategy of intentionally violating normalization rules to improve the read performance of a database. It involves adding redundant data to one or more tables to avoid costly joins in a query.
4705
The standards for which early data model were developed by the Conference on Data Systems Languages (CODASYL)?
Answer:
Network Model
The CODASYL committee was responsible for creating standards for programming languages like COBOL, and their database task group defined the specifications for the network data model.
4706
A relation is in Boyce-Codd Normal Form (BCNF) if and only if for every non-trivial functional dependency X -> Y, X is a:
Answer:
Superkey
The definition of BCNF is that for any functional dependency (X -> Y), the determinant (X) must be a superkey. This is a stricter condition than 3NF and eliminates more anomalies.
4707
The technique of focusing on a specific element in a data warehouse is called __.
Answer:
Drill down
Drill down is an analytical technique that allows users to explore data from a summary level to a more detailed level.
4708
Which TCL command is used to undo all modifications made since the beginning of the current transaction?
Answer:
`ROLLBACK`
The `ROLLBACK` command is used to discard all changes made during the current transaction, restoring the database to the state it was in at the start of that transaction.
4709
The collection of information stored in the database at a particular moment is called a(n):
Answer:
Instance
A database instance, also known as the database state, is a snapshot of the data in the database at a specific point in time. While the schema is constant, the instance changes over time as data is added, updated, and deleted.
4710
What is a primary goal of a Database Management System (DBMS)?
Answer:
To provide a way to store and retrieve data efficiently.
The core function of a DBMS is to provide an efficient and effective method for storing, managing, and retrieving data. It aims to reduce redundancy, ensure data integrity, and provide security, all contributing to efficient data handling.