Preliminary Investigation of the Interaction Between Inc D and the PH domain of CERT
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Transcript of Chapter 9 Domain Models $PH\06f522\LarmanApplUMLandPtrns\larman3EdDgmsCh01-14\09_domainModelsR2.ppt...
Chapter 9
Domain Models
$PH\06f522\LarmanApplUMLandPtrns\larman3EdDgmsCh01-14\09_domainModelsR2.ppt – RJL060911
Fig. 9.1: Sample UP Artifact Relationships
Process Sale
1. Customer arrives ...2. ...3. Cashier enters item identifier .4....
Use Case Text
Operation : enterItem (…)
Post-conditions :- . . .
Operation Contracts
Sale
date. . .
SalesLineItem
quantity
1..*1 . . .
. . .
the domain objects, attributes, and associations that undergo state changes
Domain Model
Use-Case Model
Design Model
: Register
enterItem(itemID, quantity )
: ProductCatalog
spec = getProductSpec ( itemID )
addLineItem ( spec, quantity )
: Sale
. . .
conceptual classes in the domain
inspire the names of some software classes in the design
conceptual classes –terms, concepts attributes
,
associations
Cashier : …Item ID : …...
Glossary
elaboration of some terms in the domain model
Require -ments
Business Modeling
Design
Sample UP Artifact Relationships
Fig. 9.1
Process Sale
1. Customer arrives ...2. ...3. Cashier enters item identifier.4....
Use Case Text
Operation: enterItem(…)
Post-conditions:- . . .
Operation Contracts
Sale
date. . .
SalesLineItem
quantity
1..*1 . . .
. . .
the domain objects, attributes, and associations that undergo state changes
Domain Model
Use-Case Model
Design Model
: Register
enterItem(itemID, quantity)
: ProductCatalog
spec = getProductSpec( itemID )
addLineItem( spec, quantity )
: Sale
. . .
conceptual classes in the domain inspire the names of some software classes in the design
conceptual classes – terms, concepts attributes, associations
Cashier: …Item ID: …...
Glossary
elaboration of some terms in the domain model
Require-ments
Business Modeling
Design
Sample UP Artifact Relationships
Fig. 9.2: Partial Domain Model – A Visual Dictionary
Register
Item
Store
addressname
Sale
date time
Payment
amount
SalesLineItem
quantity
Stocked-in
*
Houses
1..*
Contained-in
1..*
Records-sale-of
0..1
Paid-by
1
1
1
1
1
1
0..1
1
Captured-on
conceptor domain object
association
attributes
Fig. 9.3
Sale
dateTime
visualization of a real-world concept in the domain of interest
it is a not a picture of a software class
Fig. 9.4
SalesDatabase software artifact; not part of domain modelavo
id
software class; not part of domain model
Sale
datetime
print()
avoid
Fig. 9.5 A Conceptual Class has a symbol, an intension (metadata) and extension (data)
Sale
datetime
concept's symbol
"A sale represents the event of a purchase transaction. It has a date and time."
concept's intension
sale-1
sale-3sale-2
sale-4
concept's extension
Fig. 9.6 Lower the Representational Gap with OO Modeling
Payment
amount
Sale
datetime
Pays-for
Payment
amount: Money
getBalance(): Money
Sale
date: DatestartTime: Time
getTotal(): Money. . .
Pays-for
UP Domain ModelStakeholder's view of the noteworthy concepts in the domain.
UP Design ModelThe object-oriented developer has taken inspiration from the real world domain in creating software classes.
Therefore, the representational gap between how stakeholders conceive the domain, and its representation in software, has been lowered.
1 1
1 1
A Payment in the Domain Model is a concept, but a Payment in the Design Model is a software class. They are not the same thing, but the former inspired the naming and definition of the latter.
This reduces the representational gap.
This is one of the big ideas in object technology.
inspires objects
and names in
Fig. 9.7: Initial POS Domain Model
StoreRegister SaleItem
CashPayment
SalesLineItem
Cashier Customer
ProductCatalog
ProductDescription
Ledger
Fig. 9.8: Initial Monopoly Domain Model
Fig. 9.9: Descriptions about other things
Item
descriptionpriceserial numberitemID
ProductDescription
descriptionpriceitemID
Item
serial number
Describes Better
Worse
1 *
Multiplicity ‘*’ means 0 to many Item instances are related to one Prod’ctDescr’n.
Multiplicity ‘1’ means one Prod’ctDescr’n instance is related to some # of Items.
Many invariant attributes are duplicated;This wastes space and causes the ‘double-maintenance’ problem – RJL.
Fig. 9.10: Descriptions about Other Things
Worse
Flight
date
time
FlightDescription
number
Airport
nameDescribes flights-to
Described-by
Flight
datenumbertime
Airport
name
Flies-to
Better
1
*1
*
1
*Clockwise Rulerelation name
is unambiguous
I rearranged model Items to illustrate 2DTopological Order:(by relational multiplicity – RJL.(I use one above/left of many.) David Hay/Oracle both reverse this orientation!
Fig. 9.11
SaleRegisterRecords-current
1 1
association
Fig. 9.12
SaleRegister Records-current 0..11
association name multiplicity
-"reading direction arrow"-it has no meaning except to indicate direction of reading the association label-often excluded
Fig. 9.13
ItemStore Stocks
*
multiplicity of the role
1
Fig. 9.14
zero or more; "many"
one or more
one to 40
exactly 5
T
T
T
T
*
1..*
1..40
5
T3, 5, 8
exactly 3, 5, or 8
Fig. 9.15
ItemStore Stocks 1
or 0..1
Multiplicity should "1" or "0..1"?
The answer depends on our interest in using the model. Typically and practically, the muliplicity communicates a domain constraint that we care about being able to check in software, if this relationship was implemented or reflected in software objects or a database. For example, a particular item may become sold or discarded, and thus no longer stocked in the store. From this viewpoint, "0..1" is logical, but ...
Do we care about that viewpoint? If this relationship was implemented in software, we would probably want to ensure that an Item software instance would always be related to 1 particular Store instance, otherwise it indicates a fault or corruption in the software elements or data.
This partial domain model does not represent software objects, but the multiplicities record constraints whose practical value is usually related to our interest in building software or databases (that reflect our real-world domain) with validity checks. From this viewpoint, "1" may be the desired value.
*
Fig. 9.15
ItemStore Stocks
1or 0..1
Multiplicity should be "1" or "0..1"?
The answer depends on our interest in using the model. Typically and practically, the multiplicity communicates adomain constraint that we care about being able to check in software, if this relationship was implemented or reflectedin software objects or a database. For example, a particular item may become sold or discarded, and thus no longer
stocked in the store. From this viewpoint, "0..1" is logical, but ...
Do we care about that viewpoint? If this relationship was implemented in software, we would probably want to ensurethat an Item software instance would always be related to 1 particular Store instance, otherwise it indicates a fault or
corruption in the software elements or data.
This partial domain model does not represent software objects, but the multiplicities record constraints whose practicalvalue is usually related to our interest in building software or databases (that reflect our real-world domain) with validity
checks. From this viewpoint, "1" may be the desired value.
*
Fig. 9.16
Flight Airport
Flies-to
Flies-from
*
* 1
1
Which relation name conforms to the Clockwise Rule? - RJL
Fig. 9.17: NextGen POS: partial domain model
Register
ItemStore
Sale
CashPayment
SalesLineItem
CashierCustomer
ProductCatalog
ProductDescription
Stocks
*
Houses
1..*
Used-by
*
Contains
1..*
Describes
*
Captured-on
Contained-in
1..*
Records-sale-of
0..1
Paid-by Is-for
Logs-completed
*
Works-on
1
1
1
1 1..*
1
1
1
1
1
1
1
0..1 1
1
Ledger
Records-accounts-
for
1
1
06f522 Assignment 1a, due 9/12:Redraw, topologicallysorted; use 2-ucLetter
symbols as box labels;include dictionary of
<symbol, name> pairs.
Fig. 9.18: Monopoly partial domain model
Fig. 9.19: Class and Attributes
Sale
dateTime/ total : Money
attributes
derived attribute
Fig. 9.20: Attribute Notation in UML
Sale
- dateTime : Date- / total : Money
Private visibility attributes
Math
+ pi : Real = 3.14 {readOnly}
Public visibility readonly attribute with initialization
Person
firstNamemiddleName : [0..1]lastName
Optional value
Fig. 9.21: Recording the quantity of Items sold in a line item
SalesLineItem ItemRecords-sale-of 10..1
SalesLineItem ItemRecords-sale-of 0..1 1..*
Each line item records a separate item sale.For example, 1 tofu package.
Each line item can record a group of the same kind of items.For example, 6 tofu packages.
SalesLineItem
/quantity
ItemRecords-sale-of 0..1 1..*
derived attribute from the multiplicity value
[Here an item quantity attribute could be added to a single SalesLineItem;but it can’t be derived because there is only one associated item.]
[Now the associated item only needs to have multiplicity 1, illustrating one possible justification for evolving a conceptual model into a different design model. – RJL]
Fig. 9.22: Relate with associations, not attributes
Cashier
namecurrentRegister
Cashier
name
Register
number
Uses
Worse
Better
not a "data type" attribute
1 1
[The ‘uses’ relation implies an implicit oid or foreign key attribute in Cashier, to identify the (currently) assigned Register. –RJL ]
06f522 assignment 1b, due 9/12: Expand/redraw this model to include the temporal history of Cashier to Register assignments over time: Add new attributes and associations and state your assumptions.
Fig. 9.23: Don’t show complex concepts as attributes; use associations.
Flight
Flight
destinationWorse
BetterFlies-to Airport1 1
destination is a complex concept
Fig. 9.24: Two ways to indicate a data type property of an object.
OK
OK
ProductDescription
ProductDescription
itemId : ItemID
1Store
Store
address : Address
11 1
ItemID
idmanufacturerCodecountryCode
Address
street1street2cityName...
Fig. 9.25: Do not use attributes as foreign keys.*
Cashier
namecurrentRegisterNumber
Cashier
name
Register
number
Works-on
Worse
Better
a "simple" attribute, but being used as a foreign key to relate to another object
1 1
* Fkeys are redundant if implied by association links. Warning: This may also force surrogate keys with standard naming conventions. [Disclaimer: I Iike surrogate keys – RJL]
Fig. 9.26: Modeling Quantities
Payment
amount : Number
Payment Quantity
amount : Number
Unit
...
Payment
amount : Quantity
Has-amount1*
Is-in1*
not useful
quantities are pure data values, so are suitable to show in attribute section better
Payment
amount : Money
variation: Money is a specialized Quantity whose unit is a currency
Fig. 9.27: NextGen POS partial domain modelCan you abbreviate names and sort by fanout?
Register
id
ItemStore
nameaddress
Sale
dateTime/ total
CashPayment
amountTendered
SalesLineItem
quantity
Cashier
id
Customer
ProductCatalog
ProductDescription
itemIDdescriptionprice
Stocks
*
Houses
1..*
Used-by
*
Contains
1..*
Describes
*
Captured-on
Contained-in
1..*
Records-sale-of
0..1
Paid-by Is-for
Logs-completed
*
Works-on
1
1
1
1 1..*
1
1
1
1
1
1
1
0..1 1
1
Ledger
Records-accounts-
for
1
1
Fig. 9.27B: NextGen POS partial domain model[With abbreviated names, leveled by fanout]
Register
id
ItemStore
nameaddress
Sale
dateTime/ total
CashPayment
amountTendered
SalesLineItem
quantity
Cashier
id
Customer
ProductCatalog
ProductDescription
itemIDdescriptionprice
Stocks
*
Houses
1..*
Used-by
*
Contains
1..*
Describes
*
Captured-on
Contained-in
1..*
Records-sale-of
0..1
Paid-by Is-for
Logs-completed
*
Works-on
1
1
1
1 1..*
1
1
1
1
1
1
1
0..1 1
1
Ledger
Records-accounts-
for
1
1
Level Symbol EntityType1 LG Ledger1 PC ProductCatalog2 PD ProductDescription2 SR StoRe3 CU Customer3 CH CasHier3 IT ITem3 RG ReGister4 SA Sale5 CP CashPayment5 SL SalesLineitem
09_domainModelsR2.ppt slide 31
Fig. 9.21C: NextGen - Topological sort by fanout [and optionality]
Level Symbol EntityType
• 1 LG Ledger
• 1 PC ProductCatalog
• 2 PDProductDescription
• 2 SR StoRe
• 3 CU Customer
• 3 CH CasHier
• 3 IT ITem
• 3 RG ReGister
• 4 SA Sale
• 5 CP CashPayment• 5 SL SalesLineitem
LG PC
PDSR
CU
CH ITRG
SA
CP SL
?
09_domainModelsR2.ppt - slide 32
Fig. 9.28: Monopoly Partial Domain Model