✅ Data Analyst Interview Questions with Answers: Part-2

11. What is structured data?

Structured data is organized in rows and columns with a fixed schema, making it easy to store and query using SQL. Example: Sales tables, customer databases.

 

12. What is semi-structured data?

Semi-structured data does not follow a strict table format but contains tags or keys. Example: JSON files, XML data, API responses.

 

13. What is unstructured data?

Unstructured data has no predefined format. Example: Emails, images, videos, customer reviews text.

 

14. What is a database?

A database is an organized system used to store, manage, and retrieve data efficiently. Example: MySQL, PostgreSQL, SQL Server.

 

15. Difference between OLTP and OLAP?

OLTP (Online Transaction Processing) → Handles daily transactions (e.g., orders, payments).
OLAP (Online Analytical Processing) → Used for reporting and analysis.

 

16. What is a primary key?

A primary key uniquely identifies each record in a table. Example: Customer_ID in a customer table.

 

17. What is a foreign key?

A foreign key links one table to another using the primary key of another table. Example: Customer_ID in Orders table linking to Customers table.

 

18. What is a fact table?

Fact table contains measurable business data like sales, revenue, or quantity.

 

19. What is a dimension table?

Dimension table contains descriptive details like customer name, region, product category.

 

20. What is a data warehouse?

A data warehouse is a centralized system that stores large volumes of historical data for analysis and reporting.

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