The Halloween Problem

On this Halloween day, I think it would be interesting to revisit the Halloween problem in database systems. This is related to some anomalies in UPDATE, INSERT, DELETE statements, that will end up in unexpected results. This is also known as Halloween protection problem and discovered by IBM researchers some 35 years ago. You can read about Halloween protection problem in numerous blogs and articles. Some of the interesting ones related to SQL Server are listed below.

Halloween Protection – The Complete Series – Paul White

Halloween Protection – Craig Freedman’s SQL Server Blog

Halloween Protection – Benjamin Nevarez

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