Relational Algebra

Relational Algebra

Relational Algebra

Relational Algebra provides a collection of Algebraic operations that operate on relations(or tables) and it  gives output result in the form of tables.

 

   Operation Symbol
 Descriptions           
 1 SELECT
 σ  Select those tuples that satisfy the given Predicate
 2  PROJECT  π  Gives the content of the given Relation
 3  UNION  U  Combine all rows from the given two table
 4  SET DIFFERENCE  --  Given two tables, this gives tuples that are in table 1 but are not in table2
 5 CARTESIAN PRODUCT
 χ  Gives list of all pairs of rows from two tables
 6  RENAME  ρ

Gives a name to the result of relational algebra expressions, we can refer the result with this name

 7  SET-  INTERSECTION
∩   List rows that appear in both tables
 8  JOIN    Combine information from two or more tables
 9  DIVISION  ÷  
 10 ASSIGNMENT
 ←   It is used to store the result of Relational Algebraic expression in temporary variables.