Relational Algebra
 The fundamental operations on tables (relations).
 Underlies the semantics of SQL.
 The basis of query optimization.
Algebra
 A set of operations on values of some type, which yield values of the same type.
 E.g. +, −, ×, and ÷ are operations on numbers which yield numbers.
Relational Algebra
 An algebra for tables.
 Setoriented: a relation is a set.
