1. Generalized projection extends the projection operation by allowing arithmetic functions to be used in the projection list.

â…¡F1,F2,...,Fn(E):

where each of Fi is arithmetic expressions involving constants and attributes in the schema of the relational-algebra expression E.

2. Example. Given a relation credit info(cname; limit; credit balance), to nd how much more each person may spend, we have

â…¡cname,limit credit balance(credit info).