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Monday 22 December 2008

Business Intelligence Challenge – Product Upgrades & Migrations, Validation – 5

Once the code has been moved to the target platform (Moving the Code), whether it’s an upgrade to a newer version or migration to another newer platform, the next step is to validate the objects moved.
Validation Process involves verification or testing of the objects in the target platform to ensure that they deliver the same output as the older objects in the source platform.
Validation is a key process by which the migration or upgrade process is certified as successful, it’s usually laborious and a time consuming process. Let us see how the Validation Process can be broken into different steps and automated for saving time and for improved accuracy. We can look at the Validation process to encompass three steps, they are
  • Metadata Validation
  • Run Validation
  • Output Validation
Metadata Validation involves comparison of the metadata definitions between the existing source environment and the target environment. This requires that the metadata of the source and the target environment be captured for the comparison.
Steps Involved:
  • Capture the source metadata into a relational structure, as part of Object Consolidation we would have captured the source metadata
  • Capture the target platform metadata in a similar way into a relational structure
  • Run SQL queries to automate the metadata comparison process
Metadata Comparison would be done at the level of semantic layer definitions and individual reports. Let us take the case of metadata comparison between two semantic layers, in case of Business Objects; Universe is the semantic layer definition. After an upgrade from an older version of Business Objects to its newer version, the first level of metadata validation between the universes would be to check whether the object counts between the universes match like the classes, the objects, the filters and then further comparison on their definitions.
If there are any differences when comparing the definitions and if they fall within the known differences between the two versions (source & target) then they are good else would require code fixing in the upgraded object.
Since we always try to validate the reports by what it gives as output, the validation process is limited by the data fed in; we could miss scenarios of a filter clause not being tested. Metadata Validation can overcome the limitation in data preparation for different scenarios for testing. If a report passes through a Metadata Validation expectation then we could 100% say that the report has upgraded or migrated effectively.
Benefits:
  • Sets up a strong base on the metadata understanding, as the objects between different platforms has to be mapped and the bridges gaps identified to run automated metadata validation
  • Improved accuracy in the validation process, overcomes the limitation in data preparation
  • Enables determining issues without running the report against the data
Run Validation is to perform a dry run of the reports in an automated way to determine whether the reports run (open) successfully or not.
When we give a report to a tester, the first activity he would perform is to run the report and if it doesn’t go through the problem is reported or analysed further. We try to foresee this problem in an automated way.
Steps Involved:
  • Have scripts to invoke the reports in batch mode, as soon as the objects are upgraded invoke(open) all the upgraded reports in the batch mode
  • Capture the errors while opening/running the report into a log
  • Classify them into two categories ‘reports that ran’ and ‘reports that failed’
Some reports could fail to open because of incorrect connection details, some due to object not found etc. This process of quick run in an automated way enables to locate the failure reports immediately and also help determine the reason for the failures in one go. Limiting the data input should be considered while invoking the report.
Benefits:
  • Saves time in determining errors due to report opening or running
  • Enables building a common solution for the code fixing team, as the ‘run errors’ are consolidated
Output Validation, is to validate the output delivered by the reports. There are two levels of output validation; they are Format Validation and Data Validation.
Format Validation is to check on the format of the data presented like font size, colour, bold, label location etc which doesn’t relate to the data value.
Data Validation is to check cell by cell the data value content between the two reports.
Steps:
  • Run the source report and export the output data to excel/word
  • Run the target report and export the output data to excel/word
  • Compare the outputs for the format and the data
The best means of comparing the output of two reports is to export them to Excel and then performing a comparison between the two Excel’s. If we can export the reports to a word format then we can leverage the word compare utility, even an export to XML would enable using available utility. In case of excel we would need to build a utility that can compare the two excel sheets.
The above three validations are some of the key aspects in validating the objects of semantics and reports; let me know your thoughts on the other means of validation …

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