MDX Solutions: With Microsoft® SQL Server™ Analysis Services 2005 and Hyperion® Essbase, Second Edition

Chapter 1. A First Introduction to MDX

This first chapter introduces the syntax and semantics of the MDX (MultiDimensional eXpressions) language, looking at basic queries and the language's modular nature. We will assume that you have a basic understanding of the multidimensional structures and metadata supported by the server(s) that you work with, but we won't assume that you've ever seen MDX before. This chapter introduces most of the major aspects of an MDX query and builds an important foundation for the subsequent chapters. It also introduces you to many important parts of the language. This material may bear reading slowly and perhaps more than once if you are new to the language.

What Is MDX?

MDX is a language that expresses selections, calculations, and some metadata definitions against an Online Analytical Processing (OLAP) database, and provides some capabilities for specifying how query results are to be represented. Unlike some other OLAP languages, it is not a full report-formatting language, though. The results of an MDX query come back to a client program as data structures that must be processed in some way to look like a spreadsheet, a chart, or some other form of output. This is quite similar to how SQL works with relational databases and how its related application programming interfaces (APIs) behave. As of this writing, there are several different APIs that support MDX, including Object Linking and Embedding Data Base for Online Analytical Processing (OLE DB ...