Using Data Modeler

Figure 7Composite Aggregations Map to Identifying RelationshipsMapping Aggregations and Associations to Non-IdentifyingRelationshipsAggregations by reference (known as aggregations) and associations map tonon-identifying relationships, with the exception of many-to-many associations. Bothof these join two classes without using a “strong” relationship. You use anaggregation when you have multiple instances of a parent class owning a dependentclass. You use an association when you have classes that are independent of eachother. An aggregate or association can be mandatory, where a parent class is required,by using a multiplicity of 1 or 1..n. An association can also be optional, where a parentclass is not required, by using a multiplicity of 0..n.18 Chapter 3 - Logical Data Modeling