Software : TableDesigner Semantic Objects Software : TableDesigner 11/30/2018
Definitions A semantic object is a named collection of attributes that sufficiently describes a distinct identity Semantic objects are grouped into classes each of which has a name A semantic object has a collection of attributes Objects represent distinct identities that users recognize as independent and separate and that they want to track and report 11/30/2018
More definitions Simple attributes have a single element DateOfHire, InvoiceNumber, SalesTotal Group attributes are composites of other attributes Address which contains Street, City, State, Zip Semantic object attributes are attributes that establish a relationship between one semantic object and another STUDENT, TEACHER 11/30/2018
Example to consider What are the simple attributes? What are the group attributes? What are the semantic object attributes? 11/30/2018
Attribute Cardinality Each attribute has a minimum cardinality usually 0 or 1 PLAYER in BASEBALL_TEAM might be 9 PLAYER in BASKETBALL_TEAM 5 Soccer 11 Football 11 Each attribute has a maximum cardinality usually 1 or n PLAYER in BASEBALL_TEAM might be 25 Football 53 Soccer 16 Basketball 12 Cardinalities are shown in format n.m where n is the minimum cardinality and m is the maximum cardinality Cardinalities of groups and attributes of groups can be subtle 11/30/2018
Same Example w. Cardinalities What is the minimum cardinality of CampusAddress? What is the minimum cardinality of Building? Note: cardinalities operate only between the attribute and the container of the attribute. 11/30/2018
Object Instance 11/30/2018
Paired Attributes THERE ARE NO ONE-WAY OBJECT RELATIONSHIPS. IF AN OBJECT CONTAINS ANOTHER OBJECT, THEN THE SECOND OBJECT WILL CONTAIN THE FIRST. 11/30/2018
More definitions An object identifier is one or more object attributes that the users employ to identify object instances. A group identifier is an identifier that has more than one attribute The domain of an attribute is a description of the attribute’s possible values The domain of a simple attribute consists of both a physical and a semantic description The domain of a group attribute also consists of both a physical and a semantic description 11/30/2018
Still more definitions The portion of an object that is visible to a particular application is called the semantic object view or simply the view. 11/30/2018
Types of Attributes Necessary to describe types of objects A single-value attribute is an attribute whose maximum cardinality is one A multivalue attribute is one whose maximum cardinality is greater than one A nonobject attribute is a simple or group attribute 11/30/2018
Seven Types of Objects Simple Composite Compound Hybrid Association Objects Parent Subtype Objects Archetype/Version Objects 11/30/2018
Simple Objects A simple object is a semantic object that contains only single-value, simple or group attributes. 11/30/2018
Transformation of Simple Object 11/30/2018
Composite Objects A composite object is a semantic object that contains one or more multivalue simple or group attributes but no object attributes. 11/30/2018
Transformation of a Composite Object 11/30/2018
Transformation of a Composite Object - separate group attributes 11/30/2018
Transformation of a Composite Object - nested group attributes this diagram doesn’t correspond exactly to figure 4-18 – it just shows nesting 11/30/2018
Compound Objects 1:1 A compound object contains at least one object attribute. 11/30/2018
Transformation of a Compound Object – 1:1 11/30/2018
Transformation of a Compound Object – 1:1 – Two ways 11/30/2018
Compound Objects 1:N or N:1 11/30/2018
Transforming a Compound Object 1:N or N:1 11/30/2018
Compound Objects N:M 11/30/2018
Transformation of Compound Objects N:M 11/30/2018