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
4941
Which SQL statement is used to insert new data in a database?
Answer:
INSERT INTO
The INSERT INTO statement is used to add one or more new rows of data into a table. You specify the table and the values to be inserted for each column.
4942
In which data model can a child record have multiple parent records?
Answer:
Network model
The network model is an extension of the hierarchical model that allows a child record (member) to have relationships with multiple parent records (owners). This creates a more flexible graph-like or net-like structure, capable of representing many-to-many relationships directly.
4943
What is a multi-valued dependency?
Answer:
When one attribute's value determines a set of values for another attribute, independent of other attributes.
A multi-valued dependency (MVD) occurs when a determinant (e.g., column A) determines a set of values for another attribute (e.g., column B), and this relationship is independent of any other attributes in the table. For example, if an `Employee` can have multiple `Skills` and multiple `Projects`.
4944
In the relational model, how are logical relationships between two tables established?
Answer:
By using a foreign key in one table that references the primary key of another.
The relational model uses the values of the data itself to create relationships. A foreign key in one table contains values that match the primary key values in another table, thus linking the two tables logically.
4945
The term 'ACID' in the context of databases refers to the properties of:
Answer:
Transactions
ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably. These properties ensure data integrity even in the event of errors or power failures.
4946
Which of the following is a primary advantage of using a DBMS over a traditional file system?
Answer:
Reduced data redundancy and inconsistency
A major advantage of a DBMS is that it controls data redundancy by integrating files, which helps eliminate inconsistencies that arise when the same data is stored in multiple separate files.
4947
A table with a single-attribute primary key is automatically in which normal form?
Answer:
2NF
The rules for Second Normal Form (2NF) are concerned with eliminating partial dependencies, where a non-key attribute depends on only part of a composite primary key. If the primary key is a single attribute (not composite), there can be no partial dependencies, so the table is automatically in 2NF (assuming it is already in 1NF).
4948
What is the primary difference between a DBMS and an RDBMS?
Answer:
An RDBMS is based on the relational model, which is a specific type of DBMS.
RDBMS (Relational Database Management System) is a type of DBMS that stores data in a structured format, using rows and columns (tables), based on the principles of the relational model. All RDBMS are DBMS, but not all DBMS are RDBMS.
4949
What is a UNIQUE constraint?
Answer:
It ensures that all values in a column are different.
The UNIQUE constraint ensures that all values in a specific column (or a set of columns) are unique. Unlike a primary key, a unique constraint can allow one NULL value in some database systems.
4950
If you encounter a file named "install.exe", what is its most probable function?
Answer:
It is an executable file for installing a program.
The ".exe" extension signifies an executable file. A file named "install.exe" is almost certainly a program designed to install software onto a computer.