Jan Chomicki, Dina Goldin, Gabriel Kuper, and David Toman. Variable independence in constraint databases, November 2001. In final review for IEEE Transactions on Knowledge and Data Engineering.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....subset of C C # can be represented by the disjunction of constraints in C # . We say that C # is a decomposition of C. Clearly, all hierarchical domains are linearly decomposable. Range domains are also linearly decomposable. For example, a set of constraints C = #, 10] x [5, #) [1, 5] can be decomposed into C # = #, 1) x (5, 10] x (10, #) Discrete domains with sets are also linearly decomposable, as each constraint x is equivalent to the disjunction of # constraints x = c 1 , x = c # . This is linear because the size of the original constraint is ....

....is used in [2] in an access control language that supports periodic temporal constraints; however, this work does not deal with representation of structured resources and the general tractability of di#erent constraint domains. In comparison with work on constraint databases, Chomicki et al. [5] state Recent developments in constraint databases, in particular the research on aggregation and spatiotemporal applications, suggest a need for middle ground formalisms that preserve some of the expressive power of constraint databases and constraint query languages, while at the same time ....

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Jan Chomicki, Dina Goldin, Gabriel Kuper, and David Toman. Variable independence in constraint databases, November 2001. In final review for IEEE Transactions on Knowledge and Data Engineering.

....algebra and the only restriction is that a selection condition cannot mix spatial and nonspatial attributes. However, to prove the safety of this set one has to extend the original set of inference rules for variable independence given in [CGK96] The modified set of rules is presented in [CGK98] The query did John own any piece of land before Paul can be expressed in relational calculus as: 9t 1 :9t 2 :9x:9y:own(John; x; y; t 1 ) own(P aul; x; y; t 2 ) t 1 t 2 : This query can be translated to relational algebra in a standard way. The resulting algebraic expression has to ....

....[DGVVG97] contains, as a corollary, a first order definition of a polygon boundary (this result was obtained independently of the first version of this paper [CR97] GRS98] describes a spatial DBMS based on constraints. Other language proposals in this area include [BBC97, BK95] CGK96, CGK98] introduces the notion of variable independence constraints and studies their theoretical properties. In the context of spatiotemporal satabases, this notion captures discrete change. Further work in this direction includes [GRS99] 7 Conclusions and Future Work We have presented a novel way to ....

J. Chomicki, D. Goldin, and G. Kuper. Variable independence in constraint databases. In preparation, 1998.

....algebra and the only restriction is that a selection condition cannot mix spatial and nonspatial attributes. However, to prove the safety of this set one has to extend the original set of inference rules for variable independence given in [CGK96] The modified set of rules is presented in [CGK98] Worboys model Linear arithmetic constraint databases D CD D 0 Q(CD ) attrs independent if attrs independent Query Q no query Figure 2: Enhancing Worboys Query Language The query did John own any piece of land before Paul can be expressed in relational calculus as: 9t 1 :9t 2 ....

J. Chomicki, D. Goldin, and G. Kuper. Variable independence in constraint databases. In preparation, 1998.

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