what is etl in a data warehouse 
 etl stands for extract transform and load etl is a data process that combines data from multiple sources into one single data storage unit which is then loaded into a data warehouse or similar data system it is used in data analytics and machine learning the bottom linethe data warehouse is a company s repository of information about its business and how it has performed over time created with input from employees in each of its key departments it is the source for analysis that reveals the company s past successes and failures and informs its decision making 