摘要
以基本实体部分为例,从模型结构、表关系、模型扩展3个方面对中石油A1系统PCEDM数据模型进行了分析和研究。PCEDM涉及到基本实体的表有19张,表与表之间关系复杂;涉及的数据项(字段)有500多项,各个字段都有它固定的含义。数据模型扩展有5种途径:保留预留字段、直接在原有表中加入新的字段、增加新的子表、扩展全新的顶级结构、增加新的下拉列表选项。研究结果对于深入了解PCEDM模型,更好地维护和完善PCEDM数据库具有重要意义。
The PCEDM model of PetroChina A1 system is very complex.This paper analyzed and illustrated its model structure,table relationship,and model extendibility with an example of basic entity.The basic entity of PCEDM is related to 19 types of data tables.The relationships between the data tables are complicated.Totally these data tables have more than 500 fields,and each field has its own meaning.Five means are offered to extend the data model:setting aside reserved-fields,adding new fields,adding new sub-tables,and adding new top-level structure,and adding new drop-down pick-list.The results are helpful for understanding and refining PCEDM model.
出处
《勘探地球物理进展》
2008年第6期464-466,共3页
Progress in Exploration Geophysics
关键词
数据模型
数据表
关系
结构
扩展
data model
data table
relationship
structure
extendibility
