What is ETL (Extract, Transform, Load)?
什么是ETL（提取、转换、加载）？
ETL is a process in which data is integrated into a database or data warehouse. Data extraction is the first step in the ETL process. This selects the data from the source systems and prepares for the transformation phase. After that, the data must be transformed into the format of the target database and uploaded there.
ETL是一个将数据整合到数据库或数据仓库的过程。数据提取是ETL过程中的第一步。这就是从源系统中选择数据，为转换阶段做准备。然后，数据必须被转换为目标数据库的格式，并上传到那里。