正在加载图片...
Design Approaches Entity relationship Model(covered in this chapter Models an enterprise as a collection of entities and relationships Entity:a“ thing”or“ object” in the enterprise that is distinguishable from other objects Described by a set of attributes Relationship: an association among several entities Represented diagrammatically by an entity-relationship diagram Normalization Theory Formalize what designs are bad, and test for themDesign Approaches • Entity Relationship Model (covered in this chapter) • Models an enterprise as a collection of entities and relationships • Entity: a “thing” or “object” in the enterprise that is distinguishable from other objects • Described by a set of attributes • Relationship: an association among several entities • Represented diagrammatically by an entity-relationship diagram: • Normalization Theory • Formalize what designs are bad, and test for them
<<向上翻页向下翻页>>
©2008-现在 cucdc.com 高等教育资讯网 版权所有