Bitemporal relations Temporal database

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a bitemporal relation contains both valid , transaction time. provides both historical , rollback information. historical information (e.g.: did john live in 1992? ) provided valid time. rollback (e.g.: in 1992, did database believe john lived? ) provided transaction time. answers these example questions may not same – database may have been altered since 1992, causing queries produce different results..


the valid time , transaction time not have same single fact. example, consider temporal database storing data 18th century. valid time of these facts somewhere between 1701 , 1800. transaction time show when facts inserted database (for example, january 21, 1998).







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