There's actually much more to physical database design than tables, rows, and constraints. However, it was necessary to discuss queries in some detail before we introduced other important database objects. I call them “important” because they can play a role in tuning an application for performance and scalability. We'll discuss the “how” part later. For now, let's review what these objects are.
A view is a “pseudo-table” derived from a legal query. For example, consider the query
SELECT emp_name FROM employee;
which returns the following data:
Hannah Smith Dan Dessens Jill Arroyo
We can create a view EMPLOYEE_V for this query with the following SQL:
CREATE VIEW employee_v AS SELECT emp_name FROM employee; ...