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
141
Which term refers to the property of a model that allows it to evolve without requiring changes to other parts of the system?
Answer:
Data independence
Data independence is a key benefit of the database approach. It separates the data description (schema) from the application programs, allowing changes to be made to the data structures without affecting the programs that use them.
142
A database system is considered "self-describing" because:
Answer:
It contains a description of its own structure.
A key characteristic of a database is that it contains not only the user data but also metadata (the data dictionary or catalog) that describes the structure of the data, constraints, and other details.
143
An ad hoc query is a:
Answer:
Spur-of-the-moment question
Ad hoc queries are created as needed to retrieve specific information from a database without being pre-programmed.
144
How would you correctly write a query to select all columns from a table named 'Customers'?
Answer:
`SELECT * FROM Customers;`
The asterisk (`*`) is a wildcard character in SQL that represents "all columns". Therefore, `SELECT *` is the standard syntax for retrieving every column from the specified table.
145
Microsoft Access and Corel Paradox are examples of:
Answer:
Relational database systems
Both Microsoft Access and Corel Paradox are examples of relational database management systems (RDBMS).
146
Which of the following is a DML command?
Answer:
UPDATE
DML stands for Data Manipulation Language. Its commands are used for managing and manipulating data within schema objects. UPDATE is a DML command used to modify existing records in a table.
147
The ability to modify the physical schema without changing the logical schema is called:
Answer:
Physical data independence
Physical data independence is a characteristic of a DBMS that allows the internal storage structure (physical schema) to be changed without affecting the application programs or the conceptual (logical) schema.
148
What is a DEFAULT constraint?
Answer:
It provides a default value for a column when none is specified.
The DEFAULT constraint specifies a default value for a column. If a user does not provide a value for this column during an INSERT operation, the database system automatically assigns the defined default value.
149
A system including people, hardware, software, and activities for processing data is called an __.
Answer:
Information system
An information system is an integrated set of components for collecting, storing, and processing data and for providing information and knowledge.
150
In a large DBMS:
Answer:
Each user can "see" only a small part of the entire database
In large database systems, security and data management are handled through views or subschemas. This allows administrators to grant users access only to the specific portions of the database that are relevant to their roles, rather than exposing the entire database to everyone.