True Delta Loads of R/3 Master and Transactional Data: How It’s Done When No Standard Extractors Are Available

  • by Satish Chalasani, Independent BW/SEM Consultant
  • September 1, 2003
You might typically extract R/3 master and transactional data for which no standard extractors exist based on timestamps or as a full load. Neither method captures all the data, however. A true delta load is possible using Application Link Enabling (ALE) message types. The author describes two undocumented options for building an ALE-based extractor.

 

SAP presents few options for performing delta loads to BW from R/3 master or transactional data for which no Business Content extractors exist. This could be data from R/3 standard tables or from one of the several Z-tables you have in your R/3 system. You might typically extract this type of data as a full load nightly or monthly, or you might do a delta load based on timestamps.

Neither method performs a true delta load, however. A full load captures all changes, but it is inefficient because it transfers a lot of data unnecessarily. A delta update using timestamps can only identify new records in a table and cannot be used if the existing (old) records change or if no timestamp is in the table, which is the case most of the time. To achieve a true delta load for the described circumstances, you should use Application Link Enabling (ALE) message types.

Several of SAP's standard Business Content extractors use ALE message types to delta-enable their extractors; most of these are master data extractors. As you might have discovered, SAP has not documented how to perform a delta load using ALE without a standard extractor. I've discovered the secret through a lot of trial and error. What I've learned follows, and it applies to both BW 2.x and BW 3.x.

Satish Chalasani

Satish Chalasani is a SAP-certified independent BW/SEM consultant with more than four years of business intelligence and business analytics packaged product implementation experience. Prior to his independent status, he worked for Deloitte Consulting and Cap Gemini Ernst & Young. His data warehousing experience includes extracting data from both non-SAP and SAP products (EBP, CRM, Marketset, and R/3). His expertise also involves delivering BW content via SAP Workplace and SAP Enterprise Portal. He also does BW project reviews and project team training. Satish has been through seven BW/SEM implementations so far.

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