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
251
Which RDBMS supports full-fledged client-server application development?
Answer:
Oracle 7.1
Oracle 7.1 was a significant release that provided robust and advanced capabilities for developing and deploying client-server applications, where client machines could request services and data from a central server.
252
In which scenario would denormalization be a reasonable strategy?
Answer:
In a read-heavy data warehouse or reporting database where query speed is critical.
Denormalization is most often used in data warehousing and business intelligence applications. In these systems, data is written once but read many times for reports, so optimizing for fast data retrieval (reads) by reducing joins is a key priority.
253
The constraint that deals with the accuracy and correctness of data in the database is broadly termed:
Answer:
Data Integrity
Data integrity refers to the overall accuracy, completeness, and consistency of data. Constraints (like primary key, foreign key, check, etc.) are the mechanisms used to enforce data integrity rules.
254
A candidate key is an attribute or a set of attributes that:
Answer:
Could potentially be chosen as the table's primary key.
A candidate key is any column or combination of columns that can qualify as a unique identifier for the rows in a table. A table can have multiple candidate keys, from which one is selected to be the primary key.
255
A key that links a weak entity to its owner (strong) entity is a type of:
Answer:
Foreign Key
The relationship between a weak entity and its strong entity is maintained by a foreign key in the weak entity table that references the primary key of the strong entity table.
256
What is a "fully functional dependency"?
Answer:
When an attribute is dependent on the entire composite primary key, not just a part of it.
A fully functional dependency exists if an attribute Y is functionally dependent on a composite key X, but not on any proper subset of X. The concept is central to the definition of 2NF.
257
In a foreign key constraint, the `ON DELETE CASCADE` action specifies that:
Answer:
When a parent record is deleted, all corresponding child records should also be deleted.
`ON DELETE CASCADE` is a referential action that automatically deletes all matching records in the child table when a record in the parent table is deleted. This helps maintain referential integrity automatically.
258
The 'Entity Integrity' constraint states that:
Answer:
A primary key value cannot be NULL.
The entity integrity rule is a fundamental constraint of the relational model. It specifies that no attribute participating in the primary key of a table is allowed to have a NULL value.
259
A 'domain' in the relational model refers to:
Answer:
A set of permissible values for an attribute.
The domain of an attribute is the set of all unique, atomic values that the attribute can validly contain. For example, the domain for a 'Gender' attribute might be {'Male', 'Female', 'Other'}.
260
Which of the following contains information about the structure of a database?
Answer:
Data dictionary
A data dictionary, or metadata repository, contains information about the database's structure, including tables, columns, data types, and constraints.