My memo; ETL to OLAP, is the basic flow of how data is born and used for data analytic.
ETL stands for extract, transform and load. OLAP stands for online analytic process. (don’t know why L is there..)
Mr. E is responsible for pull data into or onto preliminary database. Mr. E may face different data sources in different format, but make them all in one unified happy data.
Mr. T is responsible for transforming data, like cleaning, reshaping, combining, filtering etc.
Mr. L is responsible for loading data for other application to be accessible, usable.
Team OLAP is responsible for reading data and generating insights.
And there are Mr. HTAP, MOLAP, ROLAP, HOLAP in the team OLAP, whom I ll introduce with more details later.
If you want total freedom and equalization you may call all or some of them Mr. , Ms. or Mrs, or however you want to call them, depending on your preference.