GIS属性数据库的关系模式分解研究

讨论了GIS属性数据库设计中关系模式的构造原理和方法 .在GIS的数据库模式设计中 ,地理实体的关系模式分解是属性数据库应用设计的关键 .在对GIS属性数据库的特征分析基础上 ,讨论了地理实体的关系模式的分解表示及其应遵循的约束条件 ,即信息无损失连接特性和保持函数依赖特性 .在关系模式的分解表示中 ,将地理实体错综复杂的关系模式分解成一组简单的属性关系集合 .同时 ,为使分解过程中不出现信息丢失并维护地学数据的完整性约束 ,还讨论了关系模式分解应满足的信息无损失连接性的约束条件 ,以及关系模式分解所应保持的函数依赖的约束因素 .

Decomposition research on relational mode for attributive database of GIS

This paper discusses building theories and approaches of relational mode for attributive database of Geographic Information System (GIS). The relational mode decomposition of geographic entities is a key problem for applied designs of attributive database in database mode planning of GIS. On the basis of characteristic analyses for attributive database of GIS, the author expounds decomposing expressions of relational mode for geographic entities, as well as restrictive properties in decomposition dependence properties. An intricate relational mode of geographic entities is decomposed into a group of simple attributive relational sets in decomposition expressions of relational mode. Meanwhile, in order to not lose information in decomposition process and to uphold the integrated restrictions of geographic data, the author also discusses restrictive conditions for joining information without loss in decomposition of relational mode, and explains restrained factors for maintaining function dependence in mode decomposition.