During extraction, validation rules are applied to test whether data has expected values essential to the data warehouse. The three words in Extract Transform Load each describe a process in the moving of data from its source to a formal data storage system (most often a data warehouse).
ETL also describes the commercial software category that automates the three processes.
What do I need to know about ETL?ĭata must be properly formatted and normalized in order to be loaded into these types of data storage systems, and ETL is used as shorthand to describe the three stages of preparing data. Extract Transform Load refers to a trio of processes that are performed when moving raw data from its source to a data warehouse, data mart, or relational database.
