G. Kuper, S. Ramaswamy, K. Shim, and J. Su. A constraint-based spatial extension to SQL. Proc. of ACM GIS, 1998.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....between valid and invalid tuples. A tuple is valid if its nested attributes are non empty sets, and invalid otherwise. Invalid tuples are discarded. The rationale behind this choice is that an object with empty space (empty nested relation) is considered as void. A different choice is adopted in [29] which permits the manipulation of objects with empty nested relations. Attribute projection t:i where i is a natural number, extracts the i th attribute of a tuple, t, if t is valid, and is undefined otherwise. For example, if t = 3; 0; f1; 2g] and t = 3; 0; fg] then t:1 = 3 while t ....

G. Kuper, S. Ramaswamy, K. Shim, and J. Su. A Constraint-Based Spatial Extension to SQL. In Proc. Intl. Symp. on Geographic Information Systems, 1998.

....of the intersection occurs during projection or the presentation of the result of the query to the user. It is unclear whether such a strategy offers any computational advantages over the approach in which the intersections are computed immediately. Recent work on spatial constraint databases [5] has proposed extensions to relational algebra that allow immediate computations of spatial object intersections. Also, our approach is potentially more general than constraint databases. For example, by moving beyond rational functions (but keeping the same basic framework) we can represent ....

G. Kuper, S. Ramaswamy, K. Shim, and J. Su. A Constraint-based Spatial Extension to SQL. In ACM Symposium on Geographic Information Systems, November 1998.

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G. Kuper, S. Ramaswamy, K. Shim, and J. Su. A constraint-based spatial extension to SQL. Proc. of ACM GIS, 1998.

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G. Kuper, S. Ramaswamy, K. Shim, and J. Su. A constraint-based spatial extension to SQL. Proc. of ACM GIS, 1998.

....a model with other basic (non spatial) types in this paper. EuAlg is a nested algebraic query language, but with only one level of nesting (this is just to provide names for spatial objects) The nested model itself similar to the ones used in [BBC97] as well as the Dedale [GRS98] and Cosmos [KRSS98] prototypes. An algebraic query language provides a better understanding of the interactions of the Euclidean constructions and querying primitives. It also provides an insight into implementation of the logic based language of [KKPV97] We now describe the line and circle drawing primitives in ....

G. Kuper, S. Ramaswamy, K. Shim, and J. Su. A constraint-based spatial extension to SQL. In Proc. of ACM Symp. on GIS, 1998.

....smallest of these values, for each geographical feature type. 3.3 Comparison with DEDALE We now show how typical queries, such as those described by the DEDALE project [5] can be expressed in CSQL. We describe a few typical queries here. Other queries in [5] expressed in CSQL, can be found in [7]. It is also straightforward to express queries from the Sequoia 2000 benchmark [9] in CSQL. In this section, we use the example given in [5] The example has the relation Grounds(name, groundtype, owner, geometry) where the attribute groundtype denotes whether the land described by geometry (a ....

G. Kuper, S. Ramaswamy, K. Shim, and J. Su. A constraintbased spatial extension to SQL. Tech. report, Bell Labs, 1998.

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