✅ 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 is primary key, if need to save students who did not...

✅ SQL Injection Malicious SQL by a hacker to be transmitted to DB, attacking the data 😈 SQL Injection Attack Delete data attack when user logs in, inputs ID and password hacker wou...

✅ Key identify the tuples(rows) uniquely in the table 🔑 Candidate Key minimal set to uniquely identify a tuple every table must have at least single candidate key can have multiple candid...

✅ Blocking/Non Blocking ⭐️ control calling method hands control over to called method 제어권을 넘겨주는가? ✔️ Blocking 제어권을 넘겨준다. calling process needs to wait for called process to ...

✅ Load Balancing sharing the work(load) to more than two servers network connection ⬆️ scale-up: increase capability of hardware scale-out: divide work among several servers ➡️ Load bal...

✅ TLS/SSL SSL Secure Socket Layer provide network transport security prevent eveasdropping, forgery of transport data of server-client encrypt data over client-server TLS ...

✅ HTTP Hypertext Transport Protocol allow data transfer in World Wide Web transmit HTML, CSS, JS operates on TCP(HTTP3 operates on UDP) use port 80 What are the two types of HTT...