Güting, R.H., Gral: An Extensible Relational Database System for Geometric Applications. Proc. of the 15th Intl. Conf. on Very Large Data Bases, 1989, 33-44. -- 17 --  Home/Search   Document Not in Database   Summary   Related Articles   Check

....the most fundamental issue in the development of spatial database systems. Spatial data types modeling objects with sharp boundaries are used routinely in the description of spatial query languages (e.g. Eg89, G 88, JC88, LN87, SH91] and have been implemented in some prototype systems (e.g. [G 89, OM88, RFS88]) even if only a few formal definitions have been given for them [G 88, GS93, GS95, GNT91, SV89] For spatial objects with undetermined boundaries analogous approaches, especially formal ones, are unknown to the author. The treatment of spatial objects with undetermined, vague, and blurred ....

R.H. Güting. Gral: An Extensible Relational Database System for Geometric Applications. Proc. of the 15th Intl. Conf. on Very Large Databases, pp. 33-44, 1989.

....user defined extensions. This 1) Praktische Informatik IV FernUniversit t Hagen D 58084 Hagen, Germany 2) Westf lische Wilhelms Universit t FB 15 Informatik, Einsteinstr. 62 D 48149 M nster, Germany 2 approach was taken, for example, in the POSTGRES [StRH90] Starburst [Haas90] Gral [G 89], PREDATOR [SeLR97] and Paradise [Pate97] projects as well as in commercial systems like Informix Universal Server [Inf98] in these cases, the model is an extended relational, or as it is called today, object relational model [St96] The second approach strives for more generality and attempts ....

Güting, R.H., Gral: An Extensible Relational Database System for Geometric Applications. Proc. of the 15th Intl. Conf. on Very Large Data Bases, 1989, 33-44. -- 17 --

....for the modeling and querying of networks. In particular, we are interested in spatially embedded networks which are an important part of geographic information, for example, highways, rivers, public transport systems, power and phone lines etc. Current spatial database models and systems (e.g. [SvH91, RoFS88, OrM88, G 89]) can well enough represent the geometry of such networks but have no concept of their connectivity. That is, one can express in a query which highways pass through a given region, but cannot find a path from a given position to a destination on the highway network. We feel that the most natural ....

....structures, implementation of the derive statement, and implementation of graph operations. 4. 1 System Architecture For a GraphDB system as an implementation of the GraphDB data model and query language we assume an extensible system architecture (see Figure 8) similar to the one used in Gral [G 89] and generalized in the SOS approach [G 93] 29 GraphDB Parser SOS Parser Optimizer SOS Parser Execution System (SECONDO) Data Structures for the Types Procedures Coroutines for the Operations Storage System Buffer Manager GraphDB DDL and Query Language Model Level Second Order ....

Güting, R.H., Gral: An Extensible Relational Database System for Geometric Applications. Proc. of the 15th Intl. Conf. on Very Large Data Bases, 1989, 33-44.

....for the modeling and querying of networks. In particular, we are interested in spatially embedded networks which are an important part of geographic information, for example, highways, rivers, public transport systems, power and phone lines etc. Current spatial database models and systems (e.g. [SvH91, RoFS88, OrM88, G 89]) can well enough represent the geometry of such networks but have no concept of their connectivity. We feel that the most natural representation of a highway network (taking it as a prototype for spatial networks) is to view it as a graph whose nodes are highway junctions, whose edges are highway ....

....will be offered by SECONDO a system based on the second order signature concept described in [G 93] which is just about to be finished. To reduce the implementation effort (that is, to make the task manageable at all) we are trying to use as much as possible modules from the Gral system [G 89], for example, storage and buffer management, index structures, data types, implementations of query processing operations (e.g. join algorithms) In a first phase, we would like to arrive at a prototype version that demonstrates some interesting part of the query processing capabilities needed ....

Güting, R.H., Gral: An Extensible Relational Database System for Geometric Applications. Proc. of the 15th Intl. Conf. on Very Large Data Bases, 1989, 33-44.

....system. The goal of our work is to provide a comprehensive framework with a clean formal basis to describe data models and query languages, representation models and execution languages, and optimization rules to map between these two levels. Some initial work in this direction has been reported [G 89] and been exemplified in a prototype, the Gral system. There, the formal basis is many sorted algebra. Such an algebra defines an application specific query language, another algebra a representation system with special kinds of index structures and query processing algorithms. Optimization rules ....

Güting, R.H., Gral: An Extensible Relational Database System for Geometric Applications. Proc. of the 15th Intl. Conf. on Very Large Data Bases, 1989, 33-44.

....not yet been implemented because they require the implementation of the object model interface (described in [G S93b] which is not yet available. The topic of this paper is the implementation of the ROSE algebra. To be precise, we must distinguish between a descriptive and an executable algebra [G 89, BeG92]. A descriptive algebra offers types and operations at a conceptual level which can be used to formulate queries; its semantics are given by defining a carrier set of objects for each sort of the algebra and a function for each operator. An executable algebra describes the actual ....

....storage management. We are currently working on the definition and implementation of a general algebra interface between an external implementation of a system of data types and a database system. The ROSE algebra will be made available under such an interface and integrated into the Gral system [G 89, BeG92]. In this approach, it is only necessary to replace the array components at the end of object representations by identifiers of so called database arrays which behave exactly like ordinary arrays but have their own page sequences and buffer management and interact properly with DBMS ....

Güting, R.H., Gral: An Extensible Relational Database System for Geometric Applications. Proc. of the 15th Intl. Conf. on Very Large Databases (Amsterdam, The Netherlands), 1989, 33-44.

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