Software engineers know very well that the earlier an error is detected in the software life-cycle, the cheapest correcting that error is. Multidimensional schemata are typically the first design artifact that is created and can be tested, so they have a primary role in ensuring early discovery of errors. All data warehouse design methodologies entail a multidimensional modeling phase, that is carried out either at a conceptual level or at a logical level. Clearly, a conceptual representation (based for instance on the DFM schemas created with indyco Builder) is by far more expressive and can more easily be understood by non-expert users.

DFM and DW Testing - A Winning CombinationRole of multidimensional test in the overall test methodology
DFM and DW Testing - A Winning Combination 2What vs. how in DW testing

Overall, adopting a methodology that entails a conceptual design phase brings several advantages in terms of design quality and accuracy and in terms of maintainability and reuse, which in return has a positive impact on the effectiveness of testing. In the next posts we will focus on functional DFM schemas testing, which aims at verifying that the multidimensional schema produced for the data mart effectively supports user requirements. It comes in three complementary types, the workload test, the hierarchy test and the conformity test.

The workload test It verifies that the workload preliminarily expressed by users during requirement analysis is actually supported by the multidimensional schema. Read more »
The hierarchy test It verifies that the functional dependencies represented by hierarchies in the multidimensional schema are actually valid on source data. Read more »
The conformity test It’s aimed at assessing how well conformed hierarchies have been designed. Read more »

Other types of tests (e.g., usability and maintainability tests) will be the subject of forthcoming posts.