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Temporal Database

This chapter delves into the concept of lifespans within the Historical Relational Data Model (HRDM). It explores the association of lifespan at three different levels: database, relation, and tuple. At the database level, we consider collections of homogeneous relations over time. Relation-level lifespans define periods in which each relation operates, while tuple-level lifespans specify timeframes for individual tuples. The chapter also introduces historical relations and domains, emphasizing the significance of these concepts in understanding temporal dimensions in data.

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Temporal Database

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  1. Temporal Database Chap 1: The Historial Relational Data Model (HRDM) Revisited

  2. 1.2 Lifespans

  3. 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.

  4. 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.

  5. 1.2 Lifespans

  6. 1.2 Lifespans

  7. 1.2 Lifespans

  8. 1.3 Historical Relations in HRDM • Set of times, T={…, t0 , t1,…} at most countably indefinite • Lifespan L: Any subset of the set T • Value domain D={D1, D2,… Dnd } • TD={TD1, TD2,… TDnd } TDi ={fi | fi : T →Di }, a partial function from T into the value domain Di TT={g| g: T →T} • Set of attributes, U ={A1, A2,… And } • Historical Domain HD HD =(TD∪ {TT})= ={TT, TD1, TD2,… TDnd } • Constant Domain CD

  9. 1.3 Historical Relations in HRDM A relation schemeR=<A, K, ALS, DOM>

  10. 1.3 Historical Relations in HRDM

  11. 1.3 Historical Relations in HRDM

  12. 1.3 Historical Relations in HRDM

  13. 1.3 Historical Relations in HRDM

  14. 1.3 Historical Relations in HRDM

  15. 1.4 The Historical Relational Algebra of HRDM

  16. 1.4 The Historical Relational Algebra of HRDM

  17. 1.4 The Historical Relational Algebra of HRDM

  18. 1.4 The Historical Relational Algebra of HRDM

  19. 1.4 The Historical Relational Algebra of HRDM

  20. 1.4 The Historical Relational Algebra of HRDM

  21. 1.4 The Historical Relational Algebra of HRDM Example??

  22. 1.4 The Historical Relational Algebra of HRDM

  23. 1.4 The Historical Relational Algebra of HRDM

  24. 1.4 The Historical Relational Algebra of HRDM θ-Join Equijoin

  25. 1.4 The Historical Relational Algebra of HRDM Natural-Join Time-Join

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