Data Warehousing and ETL is an acronym that stands for Extract, Transform, and load. It is a computer-programming process that automates the extraction, transformation and loads of a variety of types of data generated by computers from diverse sources of data and then sends the data to a repository or storage.
ETL was first introduced around a century ago in computing circles to assist computer engineers to improve the integration of data into massive mainframe computers for data processing and analysis. The ETL method was initially designed to help business intelligence requirements. It's still being used typically for smaller data repositories as well as other types of software for data integration are used to handle large amounts of data.