About the Series …
This article is a member of the series, MDX Essentials.
The series is designed to provide hands-on application of the fundamentals of
the Multidimensional Expressions (MDX) language, with each tutorial
progressively adding features designed to meet specific real-world needs.
For more information about the series in general, as well as
the software and systems requirements for getting the most out of the lessons
included, please see my first article, MDX at First Glance: Introduction to MDX Essentials.
Note: Current updates are assumed for MSSQL
Server, MSSQL Server Analysis Services, and the related Books
Online and Samples.
Overview
In
this, the first half of a two-part article, we will expose another useful
function within the MDX toolset, the .Properties function. The general
purpose of the .Properties function is to return a member property
value. Enhancements to the .Properties function allow it go beyond
returning a string containing the member property value (the
capability that the function had in Analysis Services 2000): .Properties
can now return a strongly typed result, through the use of a special flag
incorporated within Analysis Services 2005 MDX for that purpose. In
this article, we will introduce the basic .Properties function, which
returns a string in every case. We will explore the use .Properties
with the TYPED flag, whereby the property value is returned in
its internal data type, in Part II of this article.
The .Properties
function can be leveraged in many activities to present member properties
in our analysis and reporting efforts. We will introduce the basic function,
commenting upon its operation and what we can employ it to deliver. As a part
of our discussion, we will:
- Examine the syntax surrounding the function;
-
Undertake illustrative examples of the uses of the function in
practice exercises; -
Briefly discuss the results datasets we obtain in the practice
examples.
The .Properties Function
Introduction
According to the Analysis Services
Books Online, the .Properties function “returns a string, or a strongly-typed value, that
contains a member property value.” .Properties returns the value
of the specified member for the specified member property (a
member can, of course, have multiple properties), as we shall see. The
member property can be any of the intrinsic member properties,
such as NAME, ID, KEY, MEMBER_VALUE, or CAPTION,
or it can be a user-defined member property.
By default, the
value, regardless of its actual type, is coerced to be a string when we
extract it using the .Properties
function. If we make use of the TYPED
flag within the function, the return value is strongly typed, as we shall
see in Part II of this article. Here, we will consider the default
behavior, where a string is returned.
We will examine the syntax for the basic
.Properties function after a brief discussion in the next section. We will
then explore some of the possibilities .Properties offers the
knowledgeable user, within practice examples constructed to support hypothetical
business needs. This will allow us to activate what we explore in the Discussion
and Syntax sections, where we will get some hands-on exposure in
creating expressions that employ the .Properties function.
Discussion
To restate our initial explanation of its operation, the basic
.Properties function, when acting upon a member expression, returns
a string reflecting the value of the member property name that we
specify for the member expression. The .Properties function is
appended to the member expression to which we wish to apply it with the
period (“.”) delimiter. Depending upon the degree to which we leverage member
properties within our cube(s), as well as the extent to which we put those properties
to work to support information consumers within the organizations we serve, .Properties
can be used to retrieve stored member properties for many
sophisticated uses – especially when used in conjunction with a reporting
application as sophisticated as MSSQL Server 2005 Reporting Services, or
similar applications for which MDX and the .Properties function are
fully exposed. Moreover, as is often the case with MDX functions in general, when
we couple it with other functions, we can leverage .Properties to
deliver a wide range of analysis and reporting utility.
Let’s look at some syntax illustrations to further clarify
the operation of the .Properties function.
Syntax
Syntactically, in using the
basic .Properties function to return the associated member property string
value, the member upon which we seek to apply the function is specified
to the left of .Properties. The function takes the member expression (a valid MDX expression that
returns a member) to which it is appended, together with the Property
Name (a valid string expression of a member property name) we
specify – in parentheses at its right – as its arguments, and returns a string
representing the member property specified. The general syntax is
shown in the following string:
<<Member_Expression>>.Properties(Property_Name [, TYPED])
NOTE: The above syntax contains the TYPED flag,
whereby we can specify our instructions that the return value is a typed
value, based upon the original type of the member or the type
of the return value of the .Value function, as applied to the member
(depending upon whether the property type is intrinsic or user defined,
respectively). We will expand upon the use of the TYPED flag within Part
II of this article.
Putting .Properties to work is
straightforward. When using the function to return a desired property
value of the member with which we intend it to work, we simply append
the function to the right of the targeted member, enclosing a string
containing the name of the specific property for which we intend to
return a representative string value. As an illustration, let’s take a look at
a member property defined within the sample Adventure Works cube.
The Customer dimension, Customer
level members, (among many other dimensional levels within the sample cube),
contain numerous member properties. One of these properties is named
”Phone,” as depicted in Illustration 1.
Illustration 1: Member Properties Attached to the Customer
Dimension, Customer Level
As an example, within a query executed
against the cube, the information stored in the Phone member property
could be retrieved with the following pseudo-expression:
[Customer].[Customer Geography].PROPERTIES('Phone')
As is probably obvious, the .Properties
function can often be best leveraged by combining it with other functions,
particularly “relative” functions, to generate lists of names, and so forth, as
we shall see in short order.
NOTE: For information
on several of the “relative” functions, see my article
MDX
Member Functions: "Relative" Member Functions,
within the Database Journal MDX Essentials series.
We will practice some uses of the .Properties function
in the section that follows.
