403 - Database Flashcards
What is the difference between data and information?
Data are raw facts; information is processed data that has meaning.
List three advantages of using a database management system (DBMS) over manual file systems.
Improved data sharing, better data security, and efficient data access.
Name and briefly describe two types of databases.
Relational database (structured into tables) and NoSQL database (handles unstructured data).
What are the main components of a database environment?
Hardware, software, people, procedure, and data.
What is ‘Big Data’ and why is it important?
Big Data is large structured and unstructured data used for analysis and decision-making.
What are business rules in the context of database design? Provide an example.
Business rules define operational procedures; e.g., a customer can have multiple invoices.
Define an Entity and give two examples of entities in a university database.
An entity is a real-world object; examples: Student, Course.
What is the difference between a one-to-many and a many-to-many relationship? Give an example for each.
One-to-many: one department has many employees; many-to-many: students enroll in many courses.
Explain what a conceptual model is and why it is important in database design.
A conceptual model visually represents data and relationships to capture requirements accurately.
List two key objectives that good database design must meet.
Integrity and performance are key objectives of good database design.
What is the purpose of an ERD (Entity Relationship Diagram)?
ERD visually shows entities and relationships, helping to design databases.
Differentiate between composite attributes and multivalued attributes. Give an example of each.
Composite attribute: Full Address (street, city, zip); Multivalued attribute: Phone Numbers.
What is entity integrity and why is selecting a good primary key important?
Entity integrity ensures each table row is uniquely identifiable by a primary key.
Briefly explain what inheritance means in the context of ER diagrams.
Inheritance allows entities to inherit attributes from a parent entity (e.g., Employee inherits from Person).
What is entity clustering and when is it used?
Entity clustering groups related entities to simplify complex ERDs during design.
What is the purpose of normalization in databases?
Normalization organizes data to reduce redundancy and improve integrity.
Explain the difference between partial dependency and transitive dependency.
Partial: attribute depends on part of composite key; Transitive: attribute depends on non-prime attribute.
What does the acronym ACID stand for in database normalization? Briefly explain one of the principles.
ACID: Atomicity, Consistency, Isolation, Durability. Atomicity ensures all-or-nothing transactions.
What is a multi-valued dependency and how is it addressed in normalization?
Multi-valued dependency occurs when one attribute depends on another; resolved by creating separate tables.
What is the difference between an INNER JOIN and a LEFT OUTER JOIN in SQL?
INNER JOIN returns matching rows from both tables; LEFT OUTER JOIN returns all rows from the left table and matching ones from the right.
