Question

Basic structure of SQL chapter of FY BCS​

Answer 1

Basic Structure

• SQL is based on set and relational operations with certain

modifications and enhancements

• A typical SQL query has the form:

from h, r2, rm

where P

— As represent attributes

— rjs represent relations

— Pis a predicate.

• This query is equivalent to the relational algebra expression:

A1, A2, An X r2 X

X rm))

11

• The result of an SQL query is a relation.