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                ER模型分為:局部概念模型,全局概念模型,模型評審三個過程。從局部到全局,最后由模型評審來評審設計的數據庫是否符合要求。 (1)局部 定義實體,定義聯系,確定屬性,逐一畫出局部ER圖。 (2)全局 確定公共實體,合并局部,消除不一致因素,優化全局。<br/> ER模型圖有三個部分組成,如下圖: ![](https://img.kancloud.cn/c3/b6/c3b66afd9692c6a7e27a6beb959a59e2_754x344.png) 它們之間的用→連接: ![](https://img.kancloud.cn/7c/0e/7c0e58b67d5c63d0480c434b751f5a82_729x526.png)
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