Key Logical concept, structures to identify records within a table ex) Primary Key, Foreign key 통상 Key 를 생성하면 DBMS 에서 해당 key-column 에 index 를 같이 생성해 걸어준다. Index Physical structures to store the data and how to optimize data processing However, an index-only scan can return the contents of non-key columns without having to visit the index's table, since they are available directly from the index ..
