【单选题】【消耗次数：1】
下列不属于数据模型三要素的是（ ）。
①
数据结构
②
数据操作
③
数据库管理系统
④
数据完整性约束
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相关题目
【简答题】
关系数据模型的三要素是[填空]、关系操作和完整性约束条件。
【单选题】
数据模型三要素是指（ ）。
①
数据结构、数据对象和数据共享
②
数据结构、数据操作和数据完整性约束
③
数据结构、数据操作和数据的安全控制
④
数据结构、数据操作和数据的可靠性
【简答题】
什么是数据库完整性，关系数据库的数据库完整性主要有哪些？
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①
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