Managing Time in Relational Databases

Preface

Over time, things change—things like customers, products, accounts, and so forth. But most of the data we keep about things describes what they are like currently, not what they used to be like. When things change, we update the data that describes them so that the description remains current. But all these things have a history, and many of them have a future as well, and often data about their past or about their future is also important.

It is usually possible to restore and then to retrieve historical data, given enough time and effort. But businesses are finding it increasingly important to access historical data, as well as data about the future, without those associated delays and costs. More and more, business value attaches to ...