Implementing Logic in the Database

So far you have worked exclusively with tables by using Data Manipulation Language (DML) statements. You have learned to manipulate data by inserting new rows and updating or deleting existing rows. You can use many other objects in a SQL Server database to make your database applications more efficient and secure. You have also used control flow language. This chapter teaches you how to add restrictions to tables and to create other objects that help to enforce key business rules. In this chapter, you will learn about Data Definition Language (DDL) statements and constraints on tables, views, stored procedures, user-defined functions, and user-defined types. You will also learn about triggers, special objects that fire when data is modified. Because SQL Server provides so many choices for creating these objects, this chapter doesn’t attempt to explore every possible option. The chapter does, however, provide enough detail to teach you most of what you will encounter on your journey to becoming an expert T-SQL developer.