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Published byBarry Mills Modified over 7 years ago
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Chap1 Temporal Database Chap 1: The Historial Relational Data Model (HRDM) Revisited
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Chap1 1.2 Lifespans
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Chap1 1.2 Lifespans Associate a lifespan at the database level. A collection of relations that are homogeneous in the temporal dimension Associate a lifespan at the relation level. Each relation can be defined over different periods of time. All the tuples in a given relation are homogeneous.
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Chap1 1.2 Lifespans Associate a lifespan at the tuple level. Each tuple can be defined over different periods of time. All the attributes in a given tuple are homogeneous.
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Chap1 1.2 Lifespans
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Chap1 1.2 Lifespans
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Chap1 1.2 Lifespans
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Chap1 1.3 Historical Relations in HRDM Set of times, T={…, t 0, t 1,…} at most countably indefinite Lifespan L: Any subset of the set T Value domain D={D 1, D 2,… D nd } TD={TD 1, TD 2,… TD nd } TD i ={f i | f i : T → D i }, a partial function from T into the value domain D i TT={g | g : T → T} Set of attributes, U ={A 1, A 2,… A nd } Historical Domain HD HD =(TD ∪ {TT})= ={TT, TD 1, TD 2,… TD nd } Constant Domain CD
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Chap1 1.3 Historical Relations in HRDM A relation scheme R=
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Chap1 1.3 Historical Relations in HRDM
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Chap1 1.3 Historical Relations in HRDM
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Chap1 1.3 Historical Relations in HRDM
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Chap1 1.3 Historical Relations in HRDM
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Chap1 1.3 Historical Relations in HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM Example??
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM
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Chap1 1.4 The Historical Relational Algebra of HRDM θ-Join Equijoin
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Chap1 1.4 The Historical Relational Algebra of HRDM Natural-Join Time-Join
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