Introduction To MDX Dustin Ryan

A little bit about me…  Business Intelligence Consultant, Pragmatic Works  Technical editor for the many authors at Pragmatic Works   Proficient in magic  Part-time belly dancer at I-4 truck stop

About Pragmatic Works…  Located in sunny, stupid hot Green Cove Springs, FL  Offer consulting and training services  Data Warehousing  Data Migrations  DTS Conversions  Software centering around Microsoft B.I. stack  BI xPress  BIDS plugin for SSIS development  BI Documenter  Document reports, packages, cubes, databases  Task Factory  High performance SSIS tasks

What is MDX?  Multi Dimensional eXpression Language  Used to query cubes (multidimensional databases)  Developed during the late 1990’s

Where is MDX used?  Cube calculations  KPI’s  Querying the cube

Why MDX?  Allows complex reporting  Cube answers analytical questions  Data is pre-aggregated DEMO

Useful Terminology  Dimension  A Dimension organizes data in relation to a particular interest  Attribute  Within a dimension are attributes. Attributes are properties of the dimension that describe that area of interest.  Measures  A measure can be summarized as a column that contains some kind of quantifiable data that can be aggregated

More Useful Terminology  Hierarchy  A user defined hierarchy is a hierarchical structure of attributes

A couple more terms…  Level  Within a hierarchy are levels. An example of a level in the Date Hierarchy would be the Month Level.  Member  A member is a value of a level. An example of a member of the Month level would be March or April.

Yet More Useful Terms  Axis  Can be thought of as the line on a which a single dimension rests which intersects our measure groups  An MDX query can have up to 128 axes (only 5 are aliased)  Rows  Columns  Pages  Chapters  Sections  Most MDX queries contain only 2 axes since most reporting is done in a two dimensional tabular format

Basic MDX Query Syntax  MDX Query example: Select [Date].[Fiscal Year].members on Rows, [Measures].[Internet Order Quantity] on Columns From [Adventure Works] Where [Product].[Category].&[1] DEMO

Tuples & Sets  Tuples  A collection of dimension attributes not from the same dimension ex. ([Date].[Fiscal Year].members, [Sales Territory].[Sales Territory Country].members)  Set  A collection of tuples ex. {([Date].[Fiscal Year].&[2006], [Sales Reason].[Sales Reason].&[9]),([Date].[Fiscal Year].&[2006], [Sales Reason].[Sales Reason].&[5])} DEMO

Common MDX Calculations  DEMO DEMO

MDX Books to Check Out  MDX Solutions  Microsoft SQL Server 2008 MDX Step by Step  Practical MDX Queries by Art Tennick

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