2. Semantic Object Model zDefine semantic objects zUse semantic object diagrams to build data models zDefine and illustrate the 7 basic types of semantic objects zCompare semantic object and entity-relationship models

3. Data models as lenses

4. Defining Semantic Objects zSOM <> OO DB processing! zObjects: things to be represented zSemantic: carry some meaning zAttributes zIdentifiers

5. Semantic Object z“A named collection of attributes that sufficiently describes a distinct identity” ysufficient description means that the attributes represent all of the characteristics that users need ydistinct identity is something that users recognize as independent and separate zNeed not be physical

6. SO class vs. instance Distinct? Physical?

7. Attributes zTypes ySimple yGroup yObject zCardinality zDomains yPhysical ySemantic

8. Attribute Domains zDescription of an attribute’s possible values zPhysical Description ytype and length of data, constraints ycan be enumerated list yexample: RoomNumber in dept. catalog? (How about the campus catalog?) zSemantic Description (logical) yfunction or purpose of the attribute yexample: RoomNumber?

9. Let’s build an object zE.g., SOCCER-PLAYER? zProperties? zInstance? zName of semantic object? zName of semantic object instance? zSome property domains... yPhysical? ySemantic?

10. Semantic Object Diagram Object Name Group Attribute Simple Attribute Cardinality (min.max) Unique Identifier STUDENT StudentID StudentName FirstName Initial LastName PhoneNumber DEPARTMENT 0.1 1.1 1.N 1.1 ID Object Attribute (or Object Link) Non-unique Group Identifier 1.1 What is the cardinality of an identifier?

11. Domain specifications zObject specifications zDomain specifications (a)

12. Paired attributes zObject links are always paired zNo 1-way object relationships

13. Semantic Object Views

14. Roundtable Exercise zForm groups of 3 or 4; introduce yourself zLabel yourselves: 1,2,3... zOne sheet of paper and pencil per group zIn turn: yone person describes an object from the following report yanother person draws its diagram on the sheet (1 or 2 attributes) yrotate!

15. Invoice Date: 08/15/98 FILIPPO MENCZER MCI Dumb Foreigner plan ______________________________________________________________________________ Fees$6.05 Long Distance Calls$15.50 International Long Distance Calls$105.45 ______________________________________________________________________________ Total Current Charges $127.00 International Long Distance ______________________________________________________________________________ MCI Calling Plan Calls from 319-555-PROF: DATETIMERATETO/FROMNUMBERMINAMOUNT __________________________________________________________________ Jul 2910:44ASTO SWTZRLAND4127481290079.73 Aug 0210:39ASTO ITALY3933685075746.08 0312:52PSTO ITALY390680734181928.88 0801:07PXTO ITALY393368507571928.88 1412:48PSTO SWTZRLAND412748129001216.68 ______________________________________________________________________________ Total International Long Distance $105.45 Form reverse-engineering

16. Semantic Object Types zSimple zComposite zCompound zHybrid zAssociation zParent/Subtype zArchetype/Version

17. Simple Objects zOnly single-valued, non-object attributes

18. Composite Objects zOne or more multi-valued, non-object (simple or group) attributes

19. Composite Objects zMulti-valued groups can be nested Is this correct?

20. Compound Objects zHave at least one object attribute zObject attributes are always in pairs (here 1:1)

21. Compound Objects zDesigner must find out about cardinalities of paired object properties z4 types of compound objects (max card.) 1 example of each?

22. Hybrid Objects zCombination of objects of two types zAt least one multi-valued group attribute containing an object link

23. Hybrid vs. Compound Objects zWhat’s wrong with this?

24. Hybrid Object Max Cardinality zITEM in one or more SALES-ORDERS? zITEM in one or more LineItems within one SALES-ORDER?

25. Association Objects zRelates two or more objects and stores data that pertains to the relationship zTypical in resource assignments zMay or may not have its own ID

26. Parent/Subtype Objects zGeneralized object that logically contains one or more subcategories zAvoid duplication & NULLs zSubtype object attribute = IS-A attribute zInheritance ySubtype object inherits parent attributes yParent acquires all attributes of its subtypes

27. Multiple Subtypes zA parent may have more than one subtype zFor exclusivity, place subtype object attributes into a subtype group zX.Y.Z yX=min group cardinality yY=min attribute count yZ=max attribute count

28. Nested Subtypes

29. Archetype/Version Objects zArchetype object produces other objects that represent versions, releases, or editions of the archetype zVersion object ID contains archetype object link

30. E-R vs. SO Models zObjects show context (boundaries) zObjects contain multi-varied attributes zObjects contain other objects zEasier documentation (metadata)

31. E-R vs. SO Models zwhich makes better sense to you?

32. Invoice Date: 08/15/98 FILIPPO/COLLEEN MENCZER Service Summary ______________________________________________________________________________ MCI One Advantage plan fee (07/25/98 to 08/14/98) $3.03 Long Distance $15.50 International Long Distance $105.45 Other Fees $6.05 ______________________________________________________________________________ Total Current Charges $130.03 International Long Distance ______________________________________________________________________________ MCI Calling Plan Calls from 319-555-PROF: DATETIMERATETO/FROMNUMBERMINAMOUNT __________________________________________________________________ Jul 2910:44ASTO SWTZRLAND4127481290079.73 Aug 0210:39ASTO ITALY3933685075746.08 0312:52PSTO ITALY390680734181928.88 0801:07PXTO ITALY393368507571928.88 1412:48PSTO SWTZRLAND412748129001216.68 ______________________________________________________________________________ Total International Long Distance $105.45 Form reverse-engineering

33. INTERNATIONAL Country Rate INVOICE P CUSTOMER ID Name ID PhoneNumber Plan INVOICE 1.N A data model from this form LONG-DISTANCE Rate INVOICE P 0.N 1.1 1.1.1 INVOICE ID InvoiceID Date CUSTOMER Fee 0.N Call Date Time Number LONG-DISTANCE 0.ST INTERNATIONAL 0.ST Minutes Amount