At some point, people realized that 90% of data science work was building pipes and keeping them clean. And then data engineering was invented so that the data scientists wouldn't have to get their hands as dirty. :)

A snappier version which gives the flavour: Data scientists use {tensor flow, scikit-learn, parquet, hadoop, spark, scrapers, etc}. Data engineers write {tensor flow, scikit-learn, parquet, hadoop, spark, scrapers, etc}.

I'd include database engineer in that bin. We used to call people DBAs but that seems a bit limiting now.

That's a good description for a data engineer from my end.