A method for controlling a database comprises storing field definitions defining a version of the database, storing an effectivity table including descriptors corresponding to the versions and field definitions and an effective date for each and storing records with data for the fields along with a date when the record was created. When the version of the database is changed, only revised field definitions are stored and the stored effectivity table is updated only with changes in a state of field definitions and/or version changes and the effective date thereof.
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