• Select (s): It selects tuples that satisfy a given predicate.

• Project (P): It shows the list of those attributes that we wish to appear in the result.

• Cross-Product (X): It combines each row in one table with each row in the other table.

• Set-Union (U): Let there be two sets X and Y. The union operation contains all the tuples that are either in X or Y or both in X & Y.

• Set-Intersection (Ç): Let there be two tuples X and Y. The set intersection operation contains all tuples that are in both X & Y.

• Set-Difference (-): Let There be two tuples X and Y. The set intersection operation contains all tuples that are in X but not in Y.

• Renames (ρ): It renames the output relation.              

Some other operations are :

• Assignment (←)
• Outer-Join ( ]X[ )           
• G-Projection (P)

• • Aggregation ( )
• Natural-Join (|X|)