Other Important Database Objects
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; ...