Database Basics
What does DBMS stand for?
Database Management System
What is data integrity, and why is it important?
Accuracy and consistency of data in a database
What is a primary key used for?
Uniquely identifying a record
What SQL command is used to retrieve data from a database?
What is the difference bwteen a data warehouse and a data mart?
A data warehouse is organisationally-wide; a data mart is a subset for specific department
What is a collection of related data called?
A Database
How does a DBMS improve security compared to a file system?
Role-based access control, authentication, encryption
What is a foreign key, and why is it important?
A key in one table that refers to the primary key in another table to create relationships.
How do you filter results in SQL to show only customers from "New York"?
WHERE City = 'New York'
What is ETL in a data warehouse?
Extract, Transform, Load – the process of preparing data for storage.
What holds the attribute of an entity?
Field
What is data redundancy, and how does a DBMS reduce it?
Duplicate data; DBMS uses normalization and relationships to reduce it
What is normalization, and why is it important?
Process of organising data to reduce redundancy and improve integrity.
Write an SQL statement to add a new student to a Students table
INSERT INTO Students (ID, Name) VALUES (1, 'John Doe');
What is big data, and how does it relate to data warehouses?
Large, complex datasets that require special tools for analysis.
Name one function of a database management system.
Data storage, retrieval, security, etc.
What is a key advantage of DBMS over traditionsl file storage?
Reduced redunacy & Better data integrity
What is the difference between OLTP (Online Transaction Processing) and OLAP (Online Analytical Processing)?
OLTP handles real-time transactions, OLAP is used for complex data analysis and reporting.
Write an SQL query to select all students from a table named Students who have a grade above 80
SELECT * FROM Students WHERE Grade > 80
How does a data warehouse differ from an operational database?
Data warehouses store historical data for analysis; operational databases handle real-time transactions.
What is the difference between structured and unstructured data?
Structured data follows a fixed format, unstructured does not.
What is the role of a database administrator (DBA)?
Manages, secures, and optimizes the database system
What is data mining, and how is it used in business intelligence?
The process of discovering patterns and trends in large datasets to make business decisions.