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
451
Under which circumstances is a batch processing system typically the most suitable approach for data handling?
Answer:
When there is a high volume of similar data inputs that can be efficiently processed together at scheduled intervals.
Batch processing is most appropriate for scenarios involving a large volume of data that can be collected over time and processed together as a single block or 'batch.' This method is efficient when immediate, real-time processing is not critical and data can be accumulated. Examples include payroll processing, utility billing, or end-of-day financial settlements. Option (a) describes real-time processing. Option (c) also points towards real-time or interactive processing where delays are unacceptable. Option (d) is partially true for batch processing, as it can optimize overall resource use by scheduling large jobs, but the core suitability lies in the volume and non-immediacy of transactions, not solely minimizing per-transaction resource use, and it is not its primary goal. Therefore, a high volume of similar data processed together at intervals (option b) is the defining characteristic for batch processing suitability.
452
What is the main purpose of normalization?
Answer:
To minimize data redundancy
Normalization is the process of structuring a relational database to minimize data redundancy and dependency. This improves data integrity and reduces the risk of data anomalies (insertion, update, and deletion anomalies).
453
In the context of the relational model, a 'schema' refers to the:
Answer:
Design or blueprint of the database structure, including tables and their columns.
The database schema is the formal description of the database's structure. It defines the relations (tables), their attributes (columns), data types, relationships, and constraints.
454
A 'determinant' in a functional dependency (X → Y) is:
Answer:
The attribute that determines the other (X).
In the functional dependency X → Y, the attribute or set of attributes on the left side (X) is called the determinant, as its value determines the value of the attribute(s) on the right side (Y).
455
The process of normalization was first proposed by:
Answer:
E.F. Codd
E.F. Codd, the creator of the relational model, also introduced the concept of normalization and defined the first three normal forms (1NF, 2NF, 3NF) to solve the problem of data anomalies.
456
A __, or data file, is a collection of related records.
Answer:
Table
A table in a relational database is a collection of related data entries and it consists of columns and rows. It is also known as a data file.
457
In an ER diagram, a double rectangle represents a(n):
Answer:
Weak entity set
A weak entity set, which depends on a strong entity set for its existence and primary key, is represented by a double-lined rectangle.
458
A query within another query is called a:
Answer:
All of the above
All three terms—Nested Query, Subquery, and Inner Query—are used to describe a query that is embedded inside the `WHERE`, `HAVING`, `FROM`, or `SELECT` clause of another SQL query.
459
Which of the following is NOT a type of constraint?
Answer:
ORDER BY
ORDER BY is a SQL clause used in a SELECT statement to sort the result set in ascending or descending order. It is used for data retrieval and presentation, not for enforcing rules on the data stored in the table like PRIMARY KEY, FOREIGN KEY, and UNIQUE constraints.
460
A database table can have how many primary keys?
Answer:
Only one
By definition, a table can have only one primary key. However, this single primary key can be a composite key, meaning it can consist of multiple columns.