Database relational algebra

Relational algebra

•  select
• project
• Cartensian product
• Join
• Rename
• Union
• Set-intersection
• Set-difference

들이 있다.

 

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Algebra라고 하면 두가지로 나눌 수 있는데

Operands : 산술을 할때 숫자를 의미한다

Operators : 산술을 할 때 연산기호들을 나타낸다.

 

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Relational Algebra (table을 의미)

 - A Procedural language consisting of a set of operations that take one or two relations as input and produce a new relation as their output

 

Basic operators

두개의 table을 가지고 비교하며 둘은 공통된 col이 있다.

• Select
  
• Project
• Cartesian product
• Join
• Rename
  
  
• Union
• set-intersection
• set-difference