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对不起,哪个是实体结构,哪个是数据表结构?
那另一个又是什么?
关于三个概念的提问
CDM:
Conceptual Data Model to model the overall logical structure of a database, independent from any software or data storage structure considerations. A valid CDM can be converted to a PDM or an OOM.
PDM:
Physical Data Model (PDM) to model the overall physical structure of a database, taking into account DBMS software or data storage structure considerations. A valid PDM can be converted to a CDM or an OOM.
OOM:
Object Oriented Model (OOM) to model a software system using an object-oriented approach for Java or other object languages. A valid OOM can be converted to a CDM or a PDM. |
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