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
4781
Which of the following is true about a candidate key?
Answer:
It can be a primary key.
A table can have multiple keys that can uniquely identify a record; these are called candidate keys. The database administrator chooses one of these candidate keys to be the primary key for the table.
4782
A table is in 1NF if...
Answer:
it contains only atomic values.
The rule for First Normal Form (1NF) is that all columns in a table must contain only atomic (indivisible) values. This means each cell should hold a single value, and there should be no repeating groups.
4783
___ means that data stored in a database should not be accessible to unauthorized individuals.
Answer:
Data security
Data security involves protecting a database from unauthorized access, modification, or destruction.
4784
Who is known as the father of the relational model?
Answer:
E. F. Codd
Edgar F. Codd, a computer scientist at IBM, published a paper in 1970 titled "A Relational Model of Data for Large Shared Data Banks," which laid the foundation for the relational model and RDBMS.
4785
Which DML command is used to modify existing data in one or more rows of a table?
Answer:
`UPDATE`
The `UPDATE` statement is the DML command used to change or modify the values in existing records within a table. It is typically used with a `WHERE` clause to specify which rows to change.
4786
Identify the incorrect statement:
Answer:
E-commerce threats can be classified into three main categories
E-commerce threats are diverse and cannot be rigidly classified into just three main categories; they include technical, physical, and human-related risks.
4787
A DBMS provides a centralized view of data that can be accessed by multiple users from different locations. This feature is known as:
Answer:
Data Concurrency
Data concurrency is the ability of the DBMS to allow multiple users to access and modify shared data at the same time without interfering with each other, ensuring the data remains consistent.
4788
An attribute that cannot be further subdivided is called a(n):
Answer:
Atomic (or Simple) attribute
A simple or atomic attribute is one that holds a single, indivisible value. For example, `Gender` or `EmployeeID` are typically simple attributes.
4789
To remove a view from the database, you would use:
Answer:
`DROP VIEW view_name`
A view is a database object. The `DROP` command is used to remove database objects. Therefore, `DROP VIEW` is the correct command to delete a view.
4790
The object-oriented data model is based on the concepts of:
Answer:
Objects, classes, and inheritance
The object-oriented data model represents data and their relationships as objects. It uses concepts from object-oriented programming, such as classes (blueprints for objects), objects (instances of classes), methods (behavior), and inheritance.