❤️ Imperative 명령형 🆚 Declarative focus more on how Procedural Programming OOP 💙 Declarative 선언형 🆚 Imperative program by expressing logic of computation withoug talking about co...

☑️ Sequential Programming program runs by order unstructued programming 👎🏻 if need code from before, use goto need to pay attention to flow(in what order will this code be run), instead o...

☑️ Background before, developing was done through thourough planning however, these days, everything changes so fast, so many requirements, so many feedbacks before: lets plan and do agil...

✅ TDD Test Driven Development first test ➡️ then develop 👍🏻 check error simultaneously short development cycle, easier to update to client needs use automation(Junit) documentatio...

✅ Clean Code code with better readability method naming no error no repetition dependency ❌ one function per one class/method adequate spacing between functions Naming...

✅ Stored Procedure run several queries as if it is one function 👍🏻 optimization, cache easy to update less traffic between client and server with SQL security 👎🏻 less compatib...

✅ Redis normally, DB is saved on harddisk or SSD 👍🏻 Redis is saved on RAM, very fast If redis is saved on RAM, isnt RAM volatile? need backup to prevent snapshot: ba...

✅ Transaction work unit for updating database atomacity: 반영되거나, 반영되지 않거나 consistency isolation: when one transaction is working, another transaction cannot interfere durability:...

✅ DB Index to search faster in RDMS enhance query speed 👍🏻 data search faster 👍🏻 data sort faster 👍🏻 data update faster 👍🏻 efficient management of data ✔️ index a column in table...

✅ Anomaly 이상 현상 테이블을 잘못 설계하여 데이터 삽입, 삭제, 수정할 때 오류 발생 > 1. Insertion Anomaly need to add unnecessary data to instert when {student ID, course ID} is primary key, if need to sa...