Attribute Member Keys - Pt II: Composite Keys - Page 6

September 19, 2008

The Collation property affords us a way to specify the rules we wish to invoke for text data string comparisons. While collation in general has multiple purposes, it is often used to support the determination of whether the members of a given pair of strings are alike or different. Several Sort Orders are also available, with the Designator and Sort Order selections defaulting to server settings.

We noted in Part I that the Format property purports (via the Books Online and other documentation) to allow us to specify - using Visual Basic (Format function) format types - the conventions used in transforming numeric data to text, if such a transformation is required. The reality is that the only member formatting supported within the Unified Dimension Model (UDM) is the Trimming setting that we discuss below. (We can, of course, employ named calculations or column calculations (at the data source view level) within the cube to achieve our formatting ends, as alternative approaches.

The InvalidXmlCharacters property is applicable in cases where we expect data to be received in the XML format, and where we wish to dictate the handling of such data. The values are explained in Table 2.

The MimeType property allows us to specify the binary data type, where necessary to meet our needs.

The Trimming property allows us to specify the desired treatment of trailing spaces at the beginning / end of a string. As we see in Illustration 21 above, the options are self-explanatory.

Conclusion

In this, the second half of a two-part article introducing Attribute Member Keys, we continued our recent group of articles focusing upon dimensional model components, with an objective of discussing the associated concepts, and of providing hands-on exposure to the properties supporting them. We reviewed our initial introduction to the dimensional model and summarized its role in meeting the primary objectives of business intelligence. Next, we provided a brief overview of dimension attributes in general, referencing a subseries of articles, within my Introduction to MSSQL Server Analysis Services series, where we explore the properties underlying dimension attributes in detail.

We continued our exploration of Attribute Member Keys. First, we re-examined the three Attribute usage types (which we initially discussed in Attribute Member Keys – Pt I: Introduction and Simple Keys) that we can define within a containing dimension. We then narrowed our focus to the Key attribute usage type (a focus that we developed throughout Parts I and II of this article), discussing its role in meeting our business intelligence needs. We next followed with a discussion of the role of the Key attribute from a technical perspective, including its purpose within a containing dimension within Analysis Services.

We then reviewed the concepts of simple and composite keys, narrowing our exploration in this half of the article to the latter. We discussed differences between the two key types, and why composite keys are sometimes required to uniquely identify attribute members. Finally, we reviewed the Properties associated with a composite key, based upon the examination of a representative dimension attribute, Time, within our sample UDM.

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