This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=E6LbuLoU6rc&list=PLuHgQVnccGMDF6rHsY9qMuJMd295Yk4sa ================================================================================ "Concept" which is found from real world project by using "conceptual data modeling" are called "entity" table=physical_modeling(entity) ================================================================================ 글 entity = 제목 (attribute1), 본문 (attribute2), 생성일 (attribute3) columns=physical_modeling(attribute1,attribute2,attribute3) ================================================================================ Analogy: - Entity (table): directories (which can have subdirectory, and which contains relevant files) - Attributte (field): files ================================================================================ Relationship between entities ================================================================================ In logical data modeling, relationships are represented by "PK, FK", and tables are concatenated by using "Join" ================================================================================