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Data

ETL

Extract, transform, load: the batch pattern of pulling data from sources, cleaning and reshaping it, and loading it into a warehouse or database for analysis.

ETL is the classic data engineering workflow, and it still applies to IoT. A nightly job extracts the day’s readings from the time-series database, transforms them by converting units, joining with asset metadata and computing aggregates, and loads the result into reporting tables where business tools can query it. A variant, ELT, loads raw data into a data lake first and transforms inside it.

ETL suits reports and models that tolerate hours of delay. Its advantages are simplicity and reproducibility: a run can be repeated over the same period after a fix. Where reactions within seconds are needed, stream processing replaces or complements it, and the two usually share the same transformation logic.

Part of the IoT Glossary. Spotted an error or a missing term? Tell us.