August 2022
Beginner to intermediate
436 pages
9h 43m
Korean
Content preview from SQL로 시작하는 데이터 분석
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31
1
장
SQL을 활용한 분석
NOTE
_ 데이터를 웨어하우스에 저장하는 일은 주로 개인이나 팀이 담당합니다. 이 과정을
ETL
(혹은 추출
Extract
, 변환
Transform
, 로드
Load
)이라고 합니다. 추출은 자원 시스템에서 데이터를 가져오는 일을 말합니다. 변
환은 필요시 데이터의 구조를 바꾸거나 데이터를 정제하는 일입니다. 로드는 데이터를 데이터베이스에 저장
하는 일을 말합니다. 이 과정은
ELT
(추출
Extract
, 로드
Load
, 변환
Transform
)라고 부르기도 하는데, 이때 차이점은
데이터를 저장하기 전에 변환하기보다는 데이터를 저장한 후에 (주로
SQL
을 사용해) 원하는 형태로 변환하
는 과정이라는 점입니다.
ETL
에서 자원
Source
과 목표
Target
라는 용어가 사용되기도 합니다. 자원은 데이터를
가져오는 출처를 말하며 목표는 데이터베이스 및 그 안의 테이블과 같이 데이터를 저장할 공간을 의미합니다.
SQL
로 데이터 변환을 수행할 때 파이썬이나 자바 등 다른 언어를 함께 사용해 스케줄링하거나, 예외 상황이
생기면 경고를 발생시키기도 합니다. 오픈 소스뿐 아니라 수많은 상용 제품이 있으므로
ETL
을 담당하는 개
인이나 팀은 바닥부터
ETL
시스템을 개발하지 않아도 됩니다.
데이터베이스에 데이터가 저장됐으면 다음 단계는 쿼리와 분석입니다. 이 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.