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The Language of SQL- P45

The Language of SQL- P45:Research has shown that, being pressed for time, most readers tend to skip the introduction of any book they happen to read and then proceed immediately to the first real chapter. With that fact firmly in mind, we will only cover relatively unimportant material in the introduction, such as an explanation of what you will and will not learn by reading this book. | This page intentionally left blank CHAPTER 20 Strategies for Displaying Data In this final chapter we re going to return to the main theme of this book which is how to retrieve data from relational databases. In the past few chapters we ve taken a slight detour from the related topics of updating data maintaining tables and designing databases. But now we want to focus again on the role of SQL in retrieving data. More specifically we want to address situations where data is presented to users via reporting software. Beyond SQL Specialized reporting tools are often used to present data to users. Examples of this type of software include Microsoft Reporting Services and Crystal Reports. These software packages allow developers to connect to databases via SQL and they provide a well-designed user interface allowing users to easily access data via predefined reports. With minimal effort these reporting tools also enable developers to present data in a variety of formats. In addition most reporting tools enable users to export retrieved data to a spreadsheet such as Excel. This provides opportunities for users to manipulate their own data allowing them to transform data into formats unique to spreadsheets. With this in mind the purpose of this chapter is to raise an awareness on the part of the database developer of what can be accomplished either through reporting software or by users manipulating data in spreadsheets. Either way there are 207 208 Chapter 20 Strategies for Displaying Data opportunities for offloading some of the complexity that would ordinarily be involved with using SQL to other tools or the end user. Often it is easier and better for the user to play a role in the final arrangement of data than it is for the database developer to attempt to do it all in SQL. Basically we ll consider the possibility of avoiding overly complex SQL statements when similar functionality can be handled either by a reporting tool or by the user viewing the data. Reporting