Spatial Databases
Spatial Database:
(SDBMS) Spatial database is is a database that can store, manage and report on spatial data. Several GIS ( Geographic Information System) applications are built using SDBMS. SDBMS is implemented in some game engines as well.
LDB
LDB version 0.6 is an object-oriented database management system built on top of SHORE 3.0. It supports ODMG ODL specifications and can handle most ODMG OQL queries (but it is not fully ODMG-compliant yet).
The front-end:
can handle most ODL declarations;
can process most OQL queries;
supports embedded OQL in C++ with low impedance mismatch;
supports light-weight C++ and Java interfaces;
provides a visual query formulation interface;
supports transactions, updates, index creation & maintenance, macros, functions, and methods with OQL body;
extends OQL with XPath syntax to query XML data.
The query optimizer:
unnests all nested (correlated) queries;
can materialize path expressions into pointer joins;
performs semantic optimizations using ODL relationships;
uses a cost-based polynomial-time heuristic for join ordering;
uses a rule-based cost-driven optimizer to produce physical plans.
The query evaluator:
has two modes: translates evaluation plans into C++ code at compile-time or interprets the plans at run-time;
supports stream-based processing (it materializes streams only when necessary);
supports many evaluation algorithms, including sorting, block nested loop, indexed nested loop, pointer join, and sort-merge join;
supports the creation, maintenance, and use of indexes.
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LDB
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