olemus
toorandmetest (mis enamasti on struktureerimata) vajalike väljaeraldamine edasiseks töötluseks; toorandmeallikad on näiteks meilid, sidusmõõteandmed, skaneeritud tekst, veebilehed
= the process of collecting data from various sources
for the purpose of processing or storing

ülevaateid
https://www.techopedia.com/definition/25328/data-extraction
https://en.wikipedia.org/wiki/Data_extraction
http://www.learn.geekinterview.com/data-warehouse/data-extraction/what-is-data-extraction.html
http://esquiresheffield.pbworks.com/f/Extraction.pdf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4514954/
http://www.hongkiat.com/blog/web-scraping-tools/