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
4711
What is an 'Alternate Key'?
Answer:
A candidate key that is not selected as the primary key.
A table might have several candidate keys (attributes or sets of attributes that can uniquely identify a row). One is chosen as the primary key, and the remaining candidate keys are called alternate keys.
4712
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.
4713
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.
4714
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.
4715
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.
4716
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).
4717
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.
4718
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.
4719
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.
4720
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.