A reporting database copies district and sector names into a large summary table, deliberately repeating data. When is this denormalisation acceptable?
Une base de reporting recopie les noms de districts et de secteurs dans une grande table de synthèse, en répétant volontairement des données. Quand cette dénormalisation est-elle acceptable ?
Answers
AAlways, in every transactional system, because normalisation is an outdated idea from the 1970sToujours, dans tout système transactionnel, car la normalisation est une idée dépassée des années 1970
BNever; repeated data is forbidden in all databasesJamais ; les données répétées sont interdites dans toutes les bases
CFor read-heavy reporting where speed matters and data is refreshed in a controlled wayPour du reporting surtout en lecture, où la vitesse compte et où les données sont rafraîchies de façon contrôlée
DOnly when the database has no primary keysSeulement lorsque la base n'a pas de clés primaires
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