Can you explain the key features of a data migration system within a data warehouse?

This is a general or opening question. An interviewer will ask this type of question early in the interview to get you talking, to learn more about you, and to extract information they can use for subsequent questions. You can use this type of question to begin to steer the interview in a direction in which you are comfortable discussing.

For exampl: "The data migration system, which is also known as the Extract-Transform-Load (ETL) system, is the foundation of a data warehouse. A properly designed data migration system retrieves data from a variety of sources, scans and confirms the data and enforces data quality and consistency standards, and finally delivers data in a readable format. This enables application developers to use the data to build applications and end-users to use it to make informed decisions."

"The data migration system, which is also known as the Extract-Transform-Load (ETL) system, is the foundation of a data warehouse. A properly designed data migration system retrieves data from a variety of sources, scans and confirms the data and enforces data quality and consistency standards, and finally delivers data in a readable format. This enables application developers to use the data to build applications and end-users to use it to make informed decisions."