Baleen Analytics

queue.acm.org

25 points·blopeur··3 comments

The author says that the difference between ETL and ELT is that ETL extracts data from a system with well-established schema while ELT can handle schemaless data.

I thought the difference between ETL and ELT was that ETL does the transformations outside the system where the data is eventually loaded, while ELT does the transformations inside the system where the data is loaded. It has nothing to do with whether the data has a schema or not. An ETL process can work perfectly with schemaless data.

I also found the language of the author to be a bit abstract with few examples. I could not understand some paragraphs.

Then there is this unnecessary comparison with the whales.

The author also self-cites their 4 other articles.

Overall I did not like the article.

Self-citations are often hard to avoid (in particular in more formal academic writing, in which you want to establish the delta of your current work wrt. your previous works). It is striking, however, that the author exclusively cites himself. This is kind of weird, because it makes it look like the line of work is not related to anything anybody else is doing (lacks relevance).

I think the author is implying that T transforms the data (implicitly) to a target schema. So, if T comes at the end (at query time) you are in effect schematics (or using the schema implied in the query). If T comes before L you are mapping to a target schema before L.

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