https://afsdzvcx123.tistory.com/entry/WPF-%EB%AC%B8%EB%B2%95-WPF-MVVM-%ED%8C%A8%ED%84%B4-%EC%9D%B4%EC%9A%A9%ED%95%98%EC%97%AC-%EC%98%A4%EB%9D%BC%ED%81%B4-DB-%EC%97%B0%EB%8F%99%ED%95%98%EA%B8%B0
