[計算機概論]課程參與

Relational Operations
• Select: Choose rows(列)
• Project: Choose columns(行)
• Join: Assemble information from two or more relations

Join operation:
從兩個以上的表格挑選出行列,再製成新的表格
Union(聯集) operation:
聯集的row組成新的表格
Intersection(交集) oprration:
交集的row組成新的表格
Difference operation:
去掉交集後剩下的row組成新的表格


Structured Query Language (SQL) 結構化查詢語言: 用來做資料庫的存取

Operations to manipulate tuples
– insert
– update
– delete
– select