1. Software : TableDesigner
Semantic Objects
Software : TableDesigner
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2. 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
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3. 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
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4. Example to consider What are the simple attributes?
What are the group attributes?
What are the semantic object attributes?
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5. 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
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6. 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.
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7. Object Instance
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8. Paired Attributes THERE ARE NO ONE-WAY OBJECT RELATIONSHIPS.
IF AN OBJECT CONTAINS ANOTHER OBJECT, THEN THE SECOND OBJECT WILL CONTAIN THE FIRST.
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9. 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
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10. 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.
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11. 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
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12. Seven Types of Objects Simple Composite Compound Hybrid
Association Objects
Parent Subtype Objects
Archetype/Version Objects
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13. Simple Objects
A simple object is a semantic object that contains only single-value, simple or group attributes.
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14. Transformation of Simple Object
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15. Composite Objects
A composite object is a semantic object that contains one or more multivalue simple or group attributes but no object attributes.
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16. Transformation of a Composite Object
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17. Transformation of a Composite Object - separate group attributes
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18. Transformation of a Composite Object - nested group attributes this diagram doesn’t correspond exactly to figure 4-18 – it just shows nesting
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19. Compound Objects 1:1
A compound object contains at least one object attribute.
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20. Transformation of a Compound Object – 1:1
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21. Transformation of a Compound Object – 1:1 – Two ways
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22. Compound Objects 1:N or N:1
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23. Transforming a Compound Object 1:N or N:1
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24. Compound Objects N:M
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25. Transformation of Compound Objects N:M
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