Could packing be specified in terms of closed - open interval semantics without having to commit to granularity ?
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چکیده
Introduction “Temporal Data and the Relational Model”, by Hugh Darwen, Chris Date & Nikos Lorentzos, presents a solution for dealing with the problem of “temporal data” in relational databases. Some of the concepts involved in the proposed solution are interval types (data types whose values are the possible -contiguousranges of values of other, underlying, ordered types), operators to operate on such interval values (some of them, e.g. OVERLAPS(), MERGES(), ... akin to what is commonly known as Allen's interval operators, some others, e.g. UNION(), INTERSECT(), ... akin to operators that are commonly known from set theory), and two canonical forms of relations labeled “unpacked form” and “packed form”.
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