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For my own education, what is "Data Lake" ? Data wharejouse is "has-been" and that's the new hype way to call it ?

A data lake is raw, unstructured data vs. a warehouse where everything is already parsed, processed, and currently query-able is my understanding.

Thanks. I see that there is a wikipedia page now. Only started to hear about it 1 or 2 years ago and did not find to much on it at the time.