Can a database be used as DWH?

Yes, Database can be used as a Data Warehouse. Even before the data warehouse, we use database for the business. But now it's a good practice to use Data warehouse because of quick response and Analystical tools. Data warehouse is based on specific category thatswhy, we get quick response as compared to Database.

Difference between structured and UN structured data ?

Structured Data:
Is in the form of structured manner, it can be a SQL query or a script that we run on terminal of any platform to perform task is considered as structured data. This data is in uniform format.

Unstructured Data:
This data is in distributed manner. It is in scattered formed. This data contains text file, video, image, audio etc.

Roles of Data Engineer :

1. Design and develop databases, data models and tables to store data.
2. Develop ETL processes and data pipelines for data integration.
3. Monitor and optimize database performance.
4. Analyze data for patterns, trends, and insights.
5. Develop data visualizations and dashboards.
6. Troubleshoot data-related issues.
7. Implement security and privacy measures.
8. Collaborate with data scientists and business stakeholders.
9. Build API connection to fetch the data from the source target to the destination target.