In a data warehouse, the main mode of access is a relational database storage paradigm, in which the structure of the data was predetermined at the time the database was designed.
Being able to process every item of data in reasonable time removes the troublesome need for sampling and promotes an investigative approach to data, in contrast to the somewhat static nature of running predetermined reports.
The trial was stopped early in July 2011 by the data and safety monitoring board when the benefits in the Mediterranean diet groups crossed a predetermined boundary.