Chapter 5: Working with DB2 Data Using SQL and XQuery

Overview

Twenty-three and one-half percent (23.5%) of the DB2 9 Fundamentals certification exam (Exam 730) is designed to test your knowledge of the various Structured Query Language (SQL) statements and XQuery expressions that are commonly used to manipulate and retrieve data. The questions that make up this portion of the exam are intended to evaluate the following:

• Your ability to identify the Data Manipulation Language (DML) statements available with DB2

• Your ability to perform insert, update, and delete operations against a database

• Your ability to retrieve and format data using various forms of the SELECT statement

• Your ability to sort and group data retrieved by a query

• Your knowledge of what transactions are, as well as how transactions are initiated and terminated

• Your ability to invoke a user-defined function and call a stored procedure

• Your ability to access Extensible Markup Language (XML) data using XQuery expressions and the SQL/XML functions available with DB2

This chapter is designed to introduce you to the SQL statements and XQuery expressions that you need to be familiar with in order to access and manipulate data. In this chapter you will also learn what transactions are and how to terminate a transaction in such a way that all operations performed within that transaction are either applied to the database and made permanent (committed) or backed out (rolled back).