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The entity-relationship(E-R)data model is based on a perception of a real world that consists of a collection of basic objects,called（ ）,and of relationships among these objects.An entity is a“thing”or“object”in the real world that is distinguishable from other objects.Entities are described in a database by a set of（ ）.A relationship is an association among several entities.The set of all entities of the same type and the set of all relationships of the same type are termed an entity set and relationship set,respectively.The overall logical structure(schema)of a database can be expressed graphically by an E-R diagram,which is built up from the following components:（ ）represent entity set,（ ）represent attributes,etc.In addition to entities and relations,the E-R model represents certain（ ）to which the contents of a database must conform.The entity-relationship model is widely used in database design.
问题1选项
在几种不同类型的软件维护中，通常情况下（）所占工作量最大。
在()中，项目经理的权力是最小的。
在项目实施的过程中，项目经理通过项目周报中的项目进度分析图表发现机房施工进度有延期风险。项目经理立即组织相关人员进行分析，下达了关于改进措施的书面指令。该指令属于（ ）
The IT service manager resigns from a project that meets the scheduleand budget. After hiring an alternativenew manager, the team is opposed to the comments from the new manager. The team is at （） developmentstages。
（）is closet to Deming's definition of Quality。
The IT service manager has learned that a software canimprove the efficiency of current and future project tasks. Because the software is fresh to the Company. Theengineer is not familiar with the software. The lT service manager decides to send the highest level engineero attend the external training course. The proiect manager uses （） risk strategies。
The process control charts are used （）。
