Schema decryption for large extract-transform-load systems

  • Authors:
  • Alexander Albrecht;Felix Naumann

  • Affiliations:
  • Hasso Plattner Institute for Software Systems Engineering, Potsdam, Germany;Hasso Plattner Institute for Software Systems Engineering, Potsdam, Germany

  • Venue:
  • ER'12 Proceedings of the 31st international conference on Conceptual Modeling
  • Year:
  • 2012

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Abstract

Extract-Transform-Load (Etl) tools are used for the creation, maintenance, and evolution of data warehouses, data marts, and operational data stores. Etl workflows populate those systems with data from various data sources by specifying and executing a DAG of transformations. Over time, hundreds of individual workflows evolve as new sources and new requirements are integrated into the system. The maintenance and evolution of large-scale Etl systems requires much time and manual effort. A key problem is to understand the meaning of unfamiliar attribute labels in source and target databases and Etl transformations. Hard-to-read attribute labels in schemata lead to frustration and time spent to develop and understand Etl workflows. We present a schema decryption technique to support Etl developers in understanding cryptic schemata of sources, targets, and Etl transformations. For a given Etl system, our recommender-like approach leverages the large number of mapped attribute labels in existing Etl workflows to produce good and meaningful decryptions. In this way we are able to decrypt attribute labels consisting of a number of unfamiliar few-letter abbreviations, such as UNP_PEN_INT , which we decrypt to UNPAID_PENALTY_INTEREST . We evaluate our schema decryption approach on three real-world repositories of Etl workflows and show that our approach is able to suggest high-quality decryptions for cryptic attribute labels in a given schema.