| Parsing:
Before that the optimizer can operate, a high-level declarative
statement must be scanned through a parser. In traditional DB, the
types of data and functions are fixed and the parsers are relatively
simple. Spatial DB are extended by user defined types so that parsers
are more complicated SELECT L.name FROM Lake L, Service Fa WHERE Area(L.Geometry) > 20 AND
Fa.name = 'camping' AND Distance(Fa.Geometry, L.Geometry) < 50 |
Última modificación: Saturday, 19 de November de 2005, 09:33