Many people don’t know the DeWitt clause and what is its function or purpose. But when licensing policies are accepted, some database providers such as Oracle, Microsoft, to name some of the most known, including the DeWitt clause.
David DeWitt is a university professor that in the eighties to make a benchmark of a database and public the results, this not like to the provider and to court the teacher. Since then many companies including in the license DeWitt clause, which prohibits making benchmarks of their products and make them public. One more thing, the company that took dewitt trial was oracle.
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HTH – Antonio NAVARRO