ETL in Exasol

This section describes how to use ETL in Exasol.

An ETL process is the transfer of data from a source system into a target system.

• Extract: The reading of data from the source systems.
• Transform: Various data modifications, customization of data types, elimination of duplicates, aggregation, and standardization of heterogeneous data structures.
• Load: Writing data in the target system.

The source systems usually involve one or more operational databases whose data is combined into a target system. The process begins with an initial load, and the periodic loading of data occurs incrementally to keep the data warehouse up-to-date.

Instead of using the ETL tools, you can use SQL statements in the database to perform more complex data transformation than the data type conversion, such as data modifications, aggregation, or schema manipulations.

You can also consider using ELT processes for better performance. In an ELT process, the Transformation phase is performed after the Extract and Load. We recommend using ELT instead of ETL whenever possible, since ELT exploits the high performance of the parallel cluster and the database for complex operations.

See also Best Practices.